Implement a sonar processor

Hi, 

We've implemented a way for sputnik to run Sonar-runner to report issues.
We use it in conjunction with sonar-ndepend (https://github.com/criteo/sonar-ndepend) but should work with
all sonar plugins as long as they provides the line information.

Cheers
Please rename test names in "should<do_something>When<something_happens>" manner, as in rest of the project.