* lazy loading (don't try and load the image until a request to draw it
is received).
* asynchronous conversion to a loadable format.
* asynchronous loading if the image loader supports it (it doesn't).
* "simple" cropping, rotating and scaling (in that order) of the image
on the LyX screen.
* display in color, grayscale or monochrome.
We also have a forked calls dialog, although it isn't very exciting
yet because only the graphics cache makes use of the forked call controller.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@3591 a592a061-630c-0410-9148-cb99ea01b6c8
