Optimise CSS and JavaScript

Using require.js optimizer to compress all CSS and JavaScript into a single files.

Set up grunt to allow developers to run both a server and a 'debug' mode where the original non-compressed files are pulled in.

I have had to make small changes to `backbone-indexeddb` to allow it to work with '''require.js''' (@julien51) and a small change to `backbone` itself in order to achieve the same thing.

I've set up '''watch''' in `grunt` so if any CSS or JavaScript files are changed then the optimised sources are rebuilt.

The buddycloud webclient deployment script has already been updated to build the optimised files on deploy.