mocha, istanbul & karma

Used this project for try out the combination of those three tools.

- mocha
  - because had problems to get karma work with existing jasmine
  - also easier command line test running

- with istanbul, you get coverage information
```
Statements   : 87.44% ( 369/422 )
Branches     : 76.08% ( 159/209 )
Functions    : 87.1% ( 54/62 )
Lines        : 87.59% ( 360/411 )
```

- karma to run tests inside multiple browsers (Chrome and Firefox in the current config).
- you'll still need to execute `rake test:prepare` if you edit `.yml` files