an improvement suggestion

[gk]

hi guys, thank you for this great tool!

let me share a suggestion/improvement.
- when it is applicable: on a heavy sites with lots of images.
- what to do: allow moving image from spriteXXX to "Non-Sprited
Images" by dragging the particular image _outside_ of SpriteMe box
(class="spritemespritediv").

I currently do have a page with 10th (or 100th?) of images and drag-
dropping it becomes a pain.
At least I could move out unwanted images and then collapse sprive-
divs after completion - that will allow me to manage those tons of
images I do have.

Thank you!