minor cleanup, added test
added test
Grand Impovements to L2

removed from rbp crap from L1 x86 generation.
its not needed in 64 bit. also removed calls to leave, because they arent needed and are just weird.
rewriting all return instructions to readjust the stack by the correct offset first.
making sure main always has a label, so that the stack decrement can happen after it, instead of its first instruction.
added lots of L2 tests from robby (adjusted to 64 bit)