link to docs in readme, move old readme to intro.md

Author: aearly

README.md

@@ -5,214 +5,8 @@
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-*For Async v1.5.x documentation, go [HERE](https://github.com/caolan/async/blob/v1.5.2/README.md)*
-
-Async is a utility module which provides straight-forward, powerful functions
-for working with asynchronous JavaScript. Although originally designed for
-use with [Node.js](https://nodejs.org/) and installable via `npm install --save async`,
-it can also be used directly in the browser.
-
-Async is also installable via:
-
-- [bower](http://bower.io/): `bower install async`
-- [component](https://github.com/componentjs/component): `component install caolan/async`
-- [jam](http://jamjs.org/): `jam install async`
-
-Async provides around 70 functions that include the usual 'functional'
-suspects (`map`, `reduce`, `filter`, `each`…) as well as some common patterns
-for asynchronous control flow (`parallel`, `series`, `waterfall`…). All these
-functions assume you follow the Node.js convention of providing a single
-callback as the last argument of your asynchronous function -- a callback which expects an Error as its first argument -- and calling the callback once.
-
-
-## Quick Examples
-
-```js
-async.map(['file1','file2','file3'], fs.stat, function(err, results){
-    // results is now an array of stats for each file
-});
-
-async.filter(['file1','file2','file3'], function(filePath, callback) {
-  fs.access(filePath, function(err) {
-    callback(null, !err)
-  });
-}, function(err, results){
-    // results now equals an array of the existing files
-});
-
-async.parallel([
-    function(callback){ ... },
-    function(callback){ ... }
-], function(err, results) {
-    // optional callback
-};
-
-async.series([
-    function(callback){ ... },
-    function(callback){ ... }
-]);
-```
-
-There are many more functions available so take a look at the docs below for a
-full list. This module aims to be comprehensive, so if you feel anything is
-missing please create a GitHub issue for it.
-
-## Common Pitfalls [(StackOverflow)](http://stackoverflow.com/questions/tagged/async.js)
-
-### Synchronous iteration functions
-
-If you get an error like `RangeError: Maximum call stack size exceeded.` or other stack overflow issues when using async, you are likely using a synchronous iteratee.  By *synchronous* we mean a function that calls its callback on the same tick in the javascript event loop, without doing any I/O or using any timers.  Calling many callbacks iteratively will quickly overflow the stack. If you run into this issue, just defer your callback with `async.setImmediate` to start a new call stack on the next tick of the event loop.
-
-This can also arise by accident if you callback early in certain cases:
-
-```js
-async.eachSeries(hugeArray, function iteratee(item, callback) {
-    if (inCache(item)) {
-        callback(null, cache[item]); // if many items are cached, you'll overflow
-    } else {
-        doSomeIO(item, callback);
-    }
-}, function done() {
-    //...
-});
-```
-
-Just change it to:
-
-```js
-async.eachSeries(hugeArray, function iteratee(item, callback) {
-    if (inCache(item)) {
-        async.setImmediate(function () {
-            callback(null, cache[item]);
-        });
-    } else {
-        doSomeIO(item, callback);
-        //...
-    }
-});
-```
-
-Async does not guard against synchronous iteratees for performance reasons.  If you are still running into stack overflows, you can defer as suggested above, or wrap functions with [`async.ensureAsync`](#ensureAsync)  Functions that are asynchronous by their nature do not have this problem and don't need the extra callback deferral.
-
-If JavaScript's event loop is still a bit nebulous, check out [this article](http://blog.carbonfive.com/2013/10/27/the-javascript-event-loop-explained/) or [this talk](http://2014.jsconf.eu/speakers/philip-roberts-what-the-heck-is-the-event-loop-anyway.html) for more detailed information about how it works.
-
-
-### Multiple callbacks
-
-Make sure to always `return` when calling a callback early, otherwise you will cause multiple callbacks and unpredictable behavior in many cases.
-
-```js
-async.waterfall([
-    function (callback) {
-        getSomething(options, function (err, result) {
-            if (err) {
-                callback(new Error("failed getting something:" + err.message));
-                // we should return here
-            }
-            // since we did not return, this callback still will be called and
-            // `processData` will be called twice
-            callback(null, result);
-        });
-    },
-    processData
-], done)
-```
-
-It is always good practice to `return callback(err, result)`  whenever a callback call is not the last statement of a function.
+Async is a utility module which provides straight-forward, powerful functions for working with asynchronous JavaScript. Although originally designed for use with [Node.js](https://nodejs.org/) and installable via `npm install --save async`, it can also be used directly in the browser.
 
+For Documentation, visit <http://caolan.github.io/async/>
 
-### Binding a context to an iteratee
-
-This section is really about `bind`, not about `async`. If you are wondering how to
-make `async` execute your iteratees in a given context, or are confused as to why
-a method of another library isn't working as an iteratee, study this example:
-
-```js
-// Here is a simple object with an (unnecessarily roundabout) squaring method
-var AsyncSquaringLibrary = {
-    squareExponent: 2,
-    square: function(number, callback){
-        var result = Math.pow(number, this.squareExponent);
-        setTimeout(function(){
-            callback(null, result);
-        }, 200);
-    }
-};
-
-async.map([1, 2, 3], AsyncSquaringLibrary.square, function(err, result){
-    // result is [NaN, NaN, NaN]
-    // This fails because the `this.squareExponent` expression in the square
-    // function is not evaluated in the context of AsyncSquaringLibrary, and is
-    // therefore undefined.
-});
-
-async.map([1, 2, 3], AsyncSquaringLibrary.square.bind(AsyncSquaringLibrary), function(err, result){
-    // result is [1, 4, 9]
-    // With the help of bind we can attach a context to the iteratee before
-    // passing it to async. Now the square function will be executed in its
-    // 'home' AsyncSquaringLibrary context and the value of `this.squareExponent`
-    // will be as expected.
-});
-```
-
-## Download
-
-The source is available for download from
-[GitHub](https://raw.githubusercontent.com/caolan/async/master/dist/async.min.js).
-Alternatively, you can install using npm:
-
-```bash
-$ npm install --save async
-```
-
-As well as using Bower:
-
-```bash
-$ bower install async
-```
-
-You can then `require()` async as normal:
-
-```js
-var async = require("async");
-```
-
-Or require individual methods:
-
-```js
-var waterfall = require("async/waterfall");
-var map = require("async/map");
-```
-
-__Development:__ [async.js](https://raw.githubusercontent.com/caolan/async/master/dist/async.js) - 29.6kb Uncompressed
-
-### In the Browser
-
-Async should work in any ES5 environment (IE9 and above).
-
-Usage:
-
-```html
-<script type="text/javascript" src="async.js"></script>
-<script type="text/javascript">
-
-    async.map(data, asyncProcess, function(err, results){
-        alert(results);
-    });
-
-</script>
-```
-
-### ES Modules
-
-We also provide async as a collection of ES2015 modules, in an alternative `async-es` package on npm.
-
-```bash
-$ npm install --save async-es
-```
-
-```js
-import waterfall from 'async-es/waterfall';
-import async from 'async-es';
-```
-
+*For Async v1.5.x documentation, go [HERE](https://github.com/caolan/async/blob/v1.5.2/README.md)*