Add basic continuous integration

Removed a lot of stuff from the Gruntfile & package.json for the
moment to just provide what is needed to run a build.

Browser CI to be re-enabled in the near future once we have a
stable provider.
Add README
CI clean-up

1. Reorganise files like OCD
2. Disable fast mode for CI (which will never use it since the
   cache will always disappear)
3. Update grunt-ts to correctly fail on type errors with TS 1.3
Fix type warnings
Split CI from default Grunt tasks
Fix compilation failures