from Andy Braham (andybraham)
This adds support for empties to reference images and draw in the 3D view.
Modifications from the original patch.
- use an empty draw 'image' type
- use image aspect ratio for non-square-pixels
- when the image is not found, still draw the frame.
ui/ --> startup/bl_ui
op/ --> startup/bl_operators
scripts/startup/ is now the only auto-loading script dir which gives some speedup for blender loading too.
~/.blender/2.56/scripts/startup works for auto-loading scripts too.
