INT 60 - Buffit v3.0 - (NOT A VECTOR!) - INSTALLATION CHECK

Program: Buffit is a shareware scrollback utility by D.T. Hamilton
Range:	INT 60 to INT 6F, selected by searching for first free vector
Notes:	the Buffit installation check consists of testing whether the
	  interrupt vector points at the ASCII signature "Buffit  "
	there is a private entry point (see #03267) immediately following the
	  signature string, i.e. eight bytes beyond the address pointed at
	  by the interrupt vector