Moved code from CppCheckRunner into CppCheckMojo, as CppCheckRunner can
be implemented as a private class in CppCheckMojo
Added CxxTestRunner Mojo that actually runs the tests by CxxTestGen
generated and built by MSBuild. Added initial tests for CxxTestRunner
for skipping tests, failing test and passing test. Updated lifecycle to
use the new Mojo at TEST phase.
Minor tweaks to constant filed visibility in AbstractMSBuildPluginMojo.
Reworked some error messages in MojoHelper.
Added some CxxTest unit test files and modified CxxTest integration test to also run the CxxTest test executables and check for failure/success
Some refactoring on CppCheckMojo to move all the logging calls to a single place.