Reimplement dependent parsers

[intjftw]

With the new Cpp metrics plugin, the issue of dependent parsers emerged again. The name cppmetricsparser preceds cppplugin which results in the metrics are to be calculated before the cpp parser is executed, hence the metrics won't be calculated.

[mcserep]

As you mentioned, dependent parsers were a thing in CodeCompass, but never really used (at least since version Earhart or Flash), so it was removed in e7e040c. I think this feature should be easily reimplementable based on the code diff.