Files changed made to add ximage/palette control to mxds.

Changes are bracketed by
	#ifdef XIMAGE_PALETTE
	#endif
although its possible I've missed a couple

Makefile	added references to the two new files
gr_def.h	New structure for palette.
gr_anilev.c	Changed calls to gr_LoadPAL to PaletteBox
gr_dicelev.c
gr_dsplev.c
gr_isolev.c
gr_subslev.c
gr_tillev.c
gr_viewlev.c

gr_pal.c	Lots, well, some.

gr_xwi2.c	gr_MakeToggle, gr_MakeTitle
		Added check for width &/or height = 0.

gr_file.c
gr_fillev.c	Added code to support writing of palette files.


Misc

XDS normally uses one colormap per window. The modified version currently
shares one color map among all windows. Other than not being able to have
multiple maps concurrently, the only other disadvantage is that if a
dicer window is chosen, the palette split routines will be called making
non dicer images look strange. This will likely be fixed later.
