(svn r6729) -Fix r6707: [build aircraft window] solved a crash when using a grf set with a buildable helicopter with a lower EngineID than the first buildable plane
Also removed a lot of const cast as they mess up the code and didn't help much

		.CODE

PUBLIC	_get_save_esp
_get_save_esp:
		MOV	RAX,RSP
		RET

PUBLIC	_rdtsc
_rdtsc:
		RDTSC
		MOV RCX,RDX
		SHL RCX,32
		AND RAX,0FFFFFFFFh
		OR  RAX,RCX
		RET

		END