JSHint Errors/Warnings now seperated / absolute configFile-path

Hi folks,

I got 2 new features:
* configFile can also be an absolute path (my issue #43)
* Separation of Errors/Warning (issue #30)

Tests: 
* added only one test for the absolute path, an existing one does already test the relative part.
* For Errors/Warnings: This had impact to several existing tests and so I just refactored them and made them all green again.

Please review it, and I hope this could be part of 1.3.1.
Cheers,
 Sebl