Add addActor functionality; add xterm to makefile.

Add:
	src/termcrate.c
		-add addActor(Actor * actors, Actor newActor, int numAct), which
		reallocs actors and adds newActor.
		-edit fire() to add bullet to _bullets, with appropriate
		initialized values.

	makefile
		-add xterm flags, to launch game in new window with appropriate
		geometry/name.
Ref:
	makefile
		-move flags variable to compiler variable, instead of calling it
		within every compilation statement.

Rea:
	src/termcrate.h
		-add comment dividers to separate macros, structs, and
		functions.