test/test_rank_filter.py: Remove unneeded imports.
test/run_nosetest.py: Added the python script to change the PYTHONPATH to include the slib directory as there is no easy way to do this in CMake and it is needed before importing rank_filter.
CMakeLists.txt: Runs the nosetests as part of `make test`.
CMakeLists.txt: Added the Testing directory to the list of things to remove for `make reset` and `make distclean`.