Hide implementation details from cmdlinerunner.h
Now that the tests no longer need access to an actual
TrajectoryAnalysisCommandLineRunner instance, move the
ICommandLineOptionsModule inheritance into an internal class declared in
the source file. The header only provides static functions, including a
factory that returns an ICommandLineOptionsModule for use in tests.
Remove an unused function from the header.
This simplifies the code in cmdlinerunner.cpp; now the runner is only
~100 lines of code, and only the run() method has a significant amount
of code that could be simplified (some minor gains could still be
achieved elswhere, but not much).
Change-Id: I49da8f71b2107d0a4f8c4731a14345eaaee276a8