Added support for several frameworks + refactoring (try no. 2)

Hi,
This is the same as a previous pull request but I fixed a bug in detection of the google loader. The rest is same as in the previous pull request. I copied it over for convenience.
> I added support for Knockout, Ember, Handlebars, Mustache, Angular and CoffeeScript (if the 
> application includes the compiler). I've also changed the Backbone icon to the actual Backbone icon. 
> I've migrated the manifest file to version 2. I've also merged the version and framework detection logic
> (I've now realized that it could be refactored even better but I'll leave it as it is for now). I've also split 
> some html files containing js into two (e.g. popup.html into popup.html and popup.js) as now, Google 
> disallows execution of inline javascript.