INT 31 - CauseWay - "ResMemDOS" - RESIZE CONVENTIONAL MEMORY BLOCK

	AX = FF22h
	BX = new size in paragraphs
	DX = initial selector for block
Return: CF clear if successful
	CF set on error
	    AX = DOS error code (see #01680 at INT 21/AH=59h/BX=0000h)
	    BX = maximum number of paragraphs available
Note:	this function will also fail if the block is expanded past a 64K
	  boundary and the next selector is already in use
SeeAlso: AX=FF21h,AX=FF23h,INT 21/AH=49h