Update and improvement for `angular` `1.2.4` and `bootstrap-switch` `1.9.0`, implement unit test

Updated `angular` to `1.2.4` and `bootstrap-switch` to `1.9.0`.
Rewritten huge part of `bs-switch` directive, it is now working with `angular` `1.2.4` and `bootstrap-switch` `1.9.0`.
The test file for `bs-switch` existed but was not implemented, it now tests every parameter the directive takes.
Also added:
- JSHint for test files
- Working example

Closes #4 #5