The Big Image refactor!

Please read:
http://www.blender3d.org/cms/Imaging.834.0.html

Or in short:

- adding MultiLayer Image support
- recoded entire Image API
- better integration of movie/sequence Images

Was a whole load of work... went down for a week to do this. So, will need
a lot of testing! Will be in irc all evening.

source/blender/include/BIF_writeimage.h

@@ -37,7 +37,7 @@ struct ImBuf;
 struct EnvMap;
 
 void BIF_save_rendered_image(char *name);
-void BIF_save_rendered_image_fs(int zbuf);
+void BIF_save_rendered_image_fs(void);
 void BIF_save_envmap(struct EnvMap *env, char *str);
 void save_image_filesel_str(char *str);