MBox Xpos.w,Ypos.w,Xpos2.w,Ypos2.w[,Colour] Draw an unfilled box in a bitmap [to specified colour]

Draws an unfilled box according to the specified area within the currently used
chunky Bitmap to the currently used ink colour or the specified colour. Width
of the box does NOT have to be a multiple of 4 and the box should be at least
1x1 in size. The specified area should fit within the dimensions of the bitmap.
X2,Y2 is allowed to be further left or further up the screen than X1,Y1. See also
MDrawingMode for a description of the drawing modes available.