Minor documentation finalization and refactoring.

Add:
	src/screen.h
		-add overloaded varargs drawPixel() that allows the user to optionally
		specify the color of the pixel, as opposed to using the default
		TEST_COLOR.

	src/interpreter/shell.c
		-remove unnecessary usleep() from shell() main-loop, which is
		essentially accounted for by ncurses's getch() as it blocks on keyboard
		input.

Mod:
	src/**/*
		-replace multi-line comment end-delimiters "^*/$" with "^ */$", for
			consistency.