Incremental mode

[spacebat]

On a large test suite that takes a long time to run, adding new files especially by refactoring existing functionality but also just new models and tests thwarts the benefits of crystalball, but there is no information linking the new files/tests to the rest of the system. An incremental mode for crystalball would allow us to exercise the new tests and new files and add that information to the map file without taking much more time and resources to do approximately the same thing. Or is there a way to make crystalball do this already?