Option --action-hold-slide. If specified, when in slideshow mode images will not automatically change after running user action. Otherwise, slideshow images will cycle after action as usual.

1) winwidget.c winwidget.h New function winwidget_update_caption using code in winwindget_render_image. This code was removed from the latter, and replaced with a call to winwidget_update_caption.

2) Image caption is updated after running action when in slideshow mode.
3) Running action in slideshow mode no longer changes the image automatically.