#318430 by dman and drewish: Show a 'preview' image when editing imagecache presets, for easy testing.

#335780 by drewish: Actions define $image as passed by reference, but call_user_func doesn't support this.

 CVS: ----------------------------------------------------------------------

some theme function fixes and move remove memory limit and toolkit requirements to imageapi gd and imageapi where they belong respectively.

Avoid a fatal error if the filefield module is disabled after setting up imagecache as the formatter.

Small UI improvement, when there are no actions on a preset go ahead and expand the fieldset with the list so the next step is clear.