merge w3m-img for framebuffer support

* w3mimg/w3mimg.h: created
* w3mimg/x11/x11_w3mimg.c: created
* w3mimg/fb/fb_w3mimg.c: created
* w3mimgsize.c w3mimgdisplay.c: modified
* configure: modified
* XMakefile: modified
* config.h.dist: updated
From: Fumitoshi UKAI  <ukai@debian.or.jp>

w3m-img for framebuffer support
* http://homepage3.nifty.com/slokar/fb/
* w3mimg/fb/fb.c w3mimg/fb/fb.h
  w3mimg/fb/fb_img.c w3mimg/fb/fb_img.h
  w3mimg/fb/fb_gdkpixbuf.c w3mimg/fb/fb_gdkpixbuf.h
  w3mimg/fb/fb_imlib2.c w3mimg/fb/fb_imlib.h
  w3mimg/fb/readme.txt w3mimg/fb/license.txt: added
From: Hiroshi Kawashima <kei@sm.sony.co.jp>

w3mimg/fb/fb_gdkpixbuf.h

@@ -0,0 +1,15 @@
+#ifndef fb_gdkpixbuf_header
+#define fb_gdkpixbuf_header
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+
+typedef struct {
+  int width;
+  int height;
+  int rowstride;
+  int alpha;
+  GdkPixbuf *pixbuf;
+  guchar    *pixels;
+} IMAGE;
+
+#endif