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
Maybe it would be useful to change level to info. It would be hard to debug this configuration running on CI server.