Moved code that creates squashfs to rlib. Changed all returns to exits

Moved squashfs code:
	The code will be required by rupdate too, and it was cluttering up rchroot
Changed all returns to exits:
	There was no point in doing "return 1" in functions, and later
	checking if the function came back with an error just to exit,
	especially since the function handles telling the user what
	happens