Fix bug with block quote split over two paragraphs and an abutting paragraph at the start.

Closes evilstreak#96

i.e. this case:

    a
    > b

    > c

Author: ashb

lib/markdown.js

@@ -671,26 +671,33 @@ Markdown.dialects.Gruber = {
 
       var jsonml = [];
 
-      // separate out the leading abutting block, if any
+      // separate out the leading abutting block, if any. I.e. in this case:
+      //
+      //  a
+      //  > b
+      //
       if ( block[ 0 ] != ">" ) {
         var lines = block.split( /\n/ ),
-            prev = [];
+            prev = [],
+            line_no = block.lineNumber;
 
         // keep shifting lines until you find a crotchet
         while ( lines.length && lines[ 0 ][ 0 ] != ">" ) {
             prev.push( lines.shift() );
+            line_no++;
         }
 
-        // reassemble!
-        block = lines.join( "\n" );
-        jsonml.push.apply( jsonml, this.processBlock( prev.join( "\n" ), [] ) );
+        var abutting = mk_block( prev.join( "\n" ), "\n", block.lineNumber );
+        jsonml.push.apply( jsonml, this.processBlock( abutting, [] ) );
+        // reassemble new block of just block quotes!
+        block = mk_block( lines.join( "\n" ), block.trailing, line_no );
       }
 
+
       // if the next block is also a blockquote merge it in
       while ( next.length && next[ 0 ][ 0 ] == ">" ) {
         var b = next.shift();
-        block = new String(block + block.trailing + b);
-        block.trailing = b.trailing;
+        block = mk_block( block + block.trailing + b, b.trailing, block.lineNumber );
       }
 
       // Strip off the leading "> " and re-process as a block.

test/regressions.t.js

@@ -384,6 +384,16 @@ test( "blockquote", function(t, md) {
     ] ],
     "blockquote with interesting content");
 
+  t.equivalent(
+    bq.call( md, mk_block( 'p\n> a', '\n\n', 1 ), [ mk_block( '> b', '\n', 4) ]  ),
+    [ [ 'para', 'p' ],
+      [ 'blockquote',
+        [ 'para', 'a' ],
+        [ 'para', 'b' ]
+      ]
+    ],
+    "blockquote with abutting paragraph");
+
 });
 
 test( "referenceDefn", function(t, md) {