Bower and ting

This pull request removes the frontend dependencies in vendor assets and includes them via bower. I've created a .bowerrc file to set up the desired location of the components in app/assets (maybe should be vendor assets?) and a component.json that specifies some default dependencies. This now allows us to control frontend dependencies in the same manner that we controll backend dependencies.

It does require the user to have bower installed and to run "bower install" after the generator has run. Maybe this can be automated?

I've also moved the top level partials to the application folder and out of the layouts folder - I think this makes more sense but - whatevs.

In addition I've made the changes that Chris and Callum and I discussed around lists / grids / helpers css.

Finally I made the generator amend development.rb to include the Sass config to allow source maps by default. Barlow thinks this is a bad thing to do - I'm open to discussion or better ways of doing this.

I realise now that I probably should have split all these changes out into different pull requests but I didn't so suck it.