Add JS docs for reader API.
Modify existing YUI doc tags to match the JS doc style.
Add more JS docs throught the whole project.
There are still places where the doc comments are just placeholders for now.
Add in a few missing doc comments, fix up other things.
FIx up some ReaderView JSdoc type defs, moving them away from a "global" namespace.
Merge pull request #143 from readium/feature/js_doc

Add JS doc comments.