xbitmap1	simplest bitmap editor, using BitmapEdit
xbitmap2	add scrollbars to xbitmap1, using BitmapEdit
xbitmap3	add small pixmaps to xbitmap1, using BitmapEdit.  Also add file writing.
xbitmap4	implement xbitmap1 NOT USING BitmapEdit

xbitmap5	xbitmap1 with scrollbars implemented with Viewport
xbitmap6	xbitmap3 with small pixmaps implemented with Label
xbitmap7	both scrollbars and small pixmaps to xbitmap1, using BitmapEdit
xbitmap8	using BitmapEdit, both reads and writes standard bitmap files.

BitmapEdit.c	Source file for BitmapEdit widget, described in chapters 5 and 6.
BitmapEdiP.h	Private include file for BitmapEdit, described in Chapter 5.
BitmapEdit.h	Public include file for BitmapEdit, described in Chapter 5.
