Code lint & repo cleanup

This PR cleans up the code (through linting) and the repository layout. This PR is motivated by two goals:

- LESS code allows us to use programming constructs, and is used by bootstrap itself, so we possibly could import definitions and variables from it during custom compilations.
- The existing JS code is in need of some serious linting, and some changes for best-practice.

- [x] move the CSS to LESS code
- [x] lint the JS code
- [ ] add grunt file for automatic building of the minified code