ubb-vga2: move image generation out of the main program

- ubb-vga2.c (session, grab): made the frame buffer "void *" and pass
  frame buffer resolution
- ubb-vga.h: color encoding and items shared between compilation units
- ubb-vga2.c (thres, pattern, grab), grabfb.c: move to grabfb.c
- ubb-vga2.c (map): make global, for use by grabfb.c
- ubb-vga2.c (pick, pattern, tricolor, grid): removed obsolete test
  image generators
- Makefile (OBJS, ubb-vga2): added grabfb.o
- Makefile (clean): remove only .o files
- Makefile (spotless): remove only executables

ubb-vga/ubb-vga.h

@@ -0,0 +1,33 @@
+/*
+ * ubb-vga.h - Output video on UBB with more or less VGA timing
+ *
+ * Written 2011 by Werner Almesberger
+ * Copyright 2011 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef UBB_VGA_H
+#define	UBB_VGA_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+
+#define	R_VAL	(1 << 3)
+#define	G_VAL	(1 << 0)
+#define	B_VAL	(1 << 1)
+#define	Y_VAL	(1 << 2)
+
+
+void *map(off_t addr, size_t size);
+
+
+extern uint8_t thres;
+
+void grabfb(void *f, int xres, int yres);
+
+#endif /* !UBB_VGA_H */