Coveralls reporter (Work in progress)

This is a fix for #229 and it's achieved by removing the base path from the generated lcov file. 
However I marked this as WIP because I don't really know whether this fits in the way you'd like it to have and also because previously to rebasing on current master the tests were failing because the basePath wasn't set there. After rebasing it worked though but I don't know whether this was a false positive or not. 

Also I didn't sign the CLA yet, will do after you told me it's good to go :)