Added CoffeeScript examples where missing, minor other fixes such as spacing standardization (2 spaces is the standard in CoffeeScript via Ruby). Also a small set of minor JS example fixes and additional comments.
Fixes http://code.google.com/p/phantomjs/issues/detail?id=907
The callback is harmless: if the user registers a "page.onCallback = [Function]",
that will receive any JS type passed via "phantomCallback()".
Also, if the handler for ".onCallback" returns a value, that is passed back as a
return value of "phantomCallback()".
Also, added "page.onConfirm" and "page.onPrompt".
This solves [Issue #133](http://code.google.com/p/phantomjs/issues/detail?id=133).