ADMIN: Cull .cube, .h5, .h5cube from .gitignore
ADMIN: Cull .cube, .h5, .h5cube from .gitignore

Now that setup.py develop is working, there's no need to house
random test files inside the project folder structure, and eventually
there's probably going to be test data with these extensions that
I *will* want in source control.

bskinn/h5cube