grunt build and server setup

This is very rough. I'd like some feedback on the setup. Still does not include karma tests.

`grunt build` now does the following:

- cleans out dist folder
- prepares angular code for minification via ngmin
- concatenates all directives into 1 file
- uglify minifies canon-angular.js to canon-angular.min.js

`grunt server` starts up a static file server for checking out the example, dist and templates folders