INT E0 - PCROBOTS v1.41 - "L_ATAN" - GET ANGLE GIVEN SCALED TANGENT
	AX = 001Ah
	BX:CX = 100000*tangent of an angle
Return: AX = angle (-90 to +90 degrees)
SeeAlso: AX=0017h,AX=0018h,AX=0019h