Edits the current image in an external application, esp usefull when dealing with projects that have lots of images.
Basicaly-- a quck way to have the image in the gimp (using gimp-remote) without rooting around in your project tree.
Added registry variable to save the external application... and some OS context for what app to run- could somebody test on macosx+win32.
How about a python slot in the Image Menu?
