INT 31 - CauseWay - "ExecOverlay" - LOAD AND OPTIONALLY EXECUTE APP CODE

	AX = FF24h
	EBX = flags
	    bit 0: don't execute (overlay only)
	    bit 1: don't preserve relocation information
	ES:EDX -> filename (see also #03163)
	FS:ESI -> commandline (ESI = 00000000h if no commandline)
	GS:EDI -> name (CW's /o option)
Return: CF clear if successful
	    ---EBX bit 0 set---
	    CX:EDX = program entry point (CS:EIP)
	    SI = segment of PSP
	    ---EBX bit 1 set---
	    BX:EAX = initial SS:ESP
	    EDI high word = base segment
	    EDI low word = number of segments
	    EBP = start of segment definitions
	CF set on error
	    AX = error code
		0001h DOS file access error
		0002h not a CuaseWay 3P file
		0003h not enough memory
SeeAlso: AX=FF2Ah,INT 21/AH=4Bh