[MWR] Mutcat_Feline

Here's everything needed to get the cat-people going.  Support for reduced fall damage, navigation-aiding whiskers, purring, etc is desirable but a low priority ATM.

Highlights include the Sleepy and Very Sleepy mutations, intended to shorten the amount of time a character can be active--at one go, in the case of Sleepy, or total, in the case of Very Sleepy.  Would appreciate some playtesting on those.  Fair amount of other feline mutations too and I've decided that maybe it's worth keeping Beast around.

Merge when ready, please.

(As I posted in IRC: Initial testing on Very Sleepy started at the default 8 AM, got tired at 4 PM, slept until 1 AM, then tired again at 11 AM and slept to 8 PM. )