Cleaned up POV-Ray file handling. New use: solidify -p project

- solidify/Makefile (pov, disp, main.pov): call the main POV-Ray file
  $(NAME).pov, not main.pov
- solidify/Makefile: generate $(NAME).inc
- solidify/solid.h, solidify/povray.c (povray_face, povray): accept file
  name as argument and write to the specified file instead of stdout
- solidify/povray.c (height_field): added file error handling
- solidify/povray.c (height_field, povray): removed useless matrix argument
- solidify/solidify.c (usage, main): new invocation "-p project" to generate
  POV-Ray output. Removed old isatty() hack.
- solidify/Makefile: updated to use solidify -p to generate POV-Ray output

solidify/Makefile

@@ -66,26 +66,25 @@ FACE_B=$(DIR)/ben-$(NAME)-$(BOTTOM)-100um.txt.bz2
 
 .PHONY:		new run pov disp
 
-# always regenerate main.pov, e.g., if NAME is changed via the command line
-.PHONY:		main.pov
-
-
 new:		solidify
 		rm -f $(NAME).sfy
-		./solidify $(NAME).sfy $(FACE_A) $(FACE_B) $(D) >$(NAME).inc
+		./solidify $(NAME).sfy $(FACE_A) $(FACE_B) $(D)
 
 run:		solidify
-		./solidify $(NAME).sfy >$(NAME).inc
+		./solidify $(NAME).sfy
 
-pov:		main.pov
-		povray +A +P -W1280 -H900 main.pov
+pov:		$(NAME).pov $(NAME).inc
+		povray +A +P -W1280 -H900 $(NAME).pov
 
 disp:
-		display main.png
+		display $(NAME).png
 
-main.pov:	template.pov
+$(NAME).pov:	template.pov
 		sed 's/NAME/$(NAME)/' template.pov >$@ || { rm -f $@; exit 1; }
 
+$(NAME).inc:	$(NAME).sfy
+		./solidify -p $<
+
 # ----- Dependencies ----------------------------------------------------------
 
 # compile and generate dependencies, from fped, based on