core: Removal of duplicate code...

core contains two functionally equivalent blocks of code...  implimenting
	cl?, se? and bclr, bset.   During operation the case code for
	bclr and bset never get called, but as stated does not matter since
	code at the top of the block performs the EXACT same function.
	technically... using the case code SHOULD be the better performing
	option...  at the moment though, neither one seems to exhibiting
	any advantage over the other.

	modified:   simavr/sim/sim_core.c