Create generic expireActors(); README ASCII edit.

Add:
	src/termcrate.c
		-add expireActors(Actor_t * actors, int * numAct); replaces both
		expireBullets() and expireEnemies(), as both were functional
		equivalents but were hard-coded to mutate either _bullets and
		_enemies respectively.

Rem:
	src/termcrate.c
		-remove expireBullets() and expireEnemies().