Remove dependacy on source parsing to determine list of test functions

At the moment we rely on parsing the .cpp .qtt source to determine what test functions are present. This is very problematic since correctly parsing source code requires a comprehensive support for each of those languages.

Change metrics code so that testr becomes the authoritative source for the available test functions and only rely on test case parsing to list the available components. Ideally the list of components also come from testr but that is another issue.