Added support for Browserify/Webpack

[aaronroberson]

Added angular-loading-bar to module exports so that after installing via npm, the package can be required in the angular module dependency list such as:

angular.module('myApp', [require('angular-loading-bar')]);

This is helpful for Browserify and Webpack.

[chieffancypants]

I don't use either of those tools, but shouldn't this be linked to dist instead of src?

[aaronroberson]

I used src because that is what package.json was pointing to previously but I see that bower.json is referencing build so I updated it to reflect the same.

[aaronroberson]

@chieffancypants: I forgot to tag you in my response.

[chieffancypants]

Great thanks! I'll take your word for it that it's working :)