Introduce our own source parser to differentiate between source files an...

I need your opinion on this one, this patch overrides what maven defined as unit test. Because in maven we cannot have a folder structure like this

sources\dir1
sources\dir1\test
sources\dir2
sources\dir2\test

so if defining in maven sources sources\dir2, the sources\dir2\test will also be considered as source files so there will be duplicated files going to the sensor. 

To overcome this, ive introduced the property sonar.cxx.testdir so that users can specify **/test/** so all these are considered correctly as test files

However it might be a good idea to check the unittest flag, so if true than we still consider as true? 

what do you think?