Use class inheritance to merge TicaCubeFactory with CubeFactory

[jaymedina]

Suggestion from @falkben RE: Pull Request #59

"Can we use class inheritance here? It looks like most of the changes would just be in the class attributes. If we make those changes, I think we can make these changes much simpler and should be easier to maintain."

Also some commentary I initially made in TicaCubeFactory class:

NOTE: Later down the line 
        we might want to generalize CubeFactory so that we no longer need 
        a separate class for the TICA cubes. 
        
        Modifying the __init__ 
        in CubeFactory so that it can switch parameters based on whether 
        we want cubes for TICA or TESS will probably be the route I take.
        Or see how this is generalized when Zcut wraps CubeFactory?