INT 10,FE - Get DESQView/TopView Virtual Screen Regen Buffer

	AH = FE
	ES:DI = set to sentinel value (test for INT 10,FE supported)


	returns:
	ES:DI = address of DESQView/TopView video buffer, DI will always
		be zero


	- on return ES:DI should be tested against the original value;
	  the value will change if this function is supported (DESQView
	  or TopView loaded), otherwise it will remain unchanged
	- if ES:DI changes this address can be used as the video screen
	  regen buffer