Big commit in orange: Interface icons for materials, textures

world and lamp. Also for images in pupmenus.
Also preparation for work on using preview images in imagebrowser.

-- Andrea

source/blender/src/SConscript

@@ -100,6 +100,7 @@ source_files = ['B.blend.c',
                 'interface.c',
                 'interface_panel.c',
                 'interface_draw.c',
+                'interface_icons.c',
                 'keyval.c',
                 'lorem.c',
                 'mainqueue.c',