Begin integrating sprite / animation / game layer

[gdamore]

The proxima5 game has created some very nice modules that would be very useful to implement as common gaming layer, and make a sub package of tcell. Think tcell/sprite or somesuch.

[gdamore]

I think probably this will be in a separate package, not in tcell.

In retrospect, even tcell/views was a mistake -- better to have consuming packages in their own tree, and keep tcell unopinionated about frameworks that use it.