Created "Extending Tux Paint" document; extracted from README.

docs/Makefile

@@ -7,17 +7,18 @@
 # Bill Kendrick
 # bill@newbreedsoftware.com
 # 
-# Sept. 4, 2005 - October 9, 2005
+# Sept. 4, 2005 - March 8, 2006
 # $Id$
 
 LINKS=links -dump -no-numbering -no-references
 
-all:	README.txt OPTIONS.txt FAQ.txt
+all:	README.txt OPTIONS.txt FAQ.txt EXTENDING.txt
 
 clean:
 	-rm README.txt
 	-rm OPTIONS.txt
 	-rm FAQ.txt
+	-rm EXTENDING.txt
 
 README.txt:	html/README.html
 	$(LINKS) $< > $@
@@ -28,3 +29,6 @@ OPTIONS.txt:	html/OPTIONS.html
 FAQ.txt:	html/FAQ.html
 	$(LINKS) $< > $@
 
+EXTENDING.txt:	html/EXTENDING.html
+	$(LINKS) $< > $@
+