support annotations from closure compiler (that jsdoc does not have)

[aretecode]

I found there are some properties I'd like to document that jsdoc does not have built in

esdoc/esdoc#347
http://stackoverflow.com/questions/25314979/documenting-side-effects-of-javascript-methods
https://github.com/google/closure-compiler/wiki/Annotating-JavaScript-for-the-Closure-Compiler#nosideeffects-modifies-thisarguments

[neogeek]

I'll definitely look into this as I'd like to support more advanced JSDoc functionality going forward. For now the functionality of doxdox is tightly coupled to the limitations of dox. I'll add this to my list of things to consider when researching other parsers to support.