Messing around with the Gruntfile

I cleaned this up based on looking through the configuration for a few other angular projects / boilerplate. 

- Less is now run through the contributed grunt task stuff rather than homegroan.
- Added `grunt webserver` from the default so you don't need to run `python -m SimpleHTTPServer` or whatever thing you like. 
- Added karma tasks; still needs to be built out.
- Starting to sketch out a build task.