A few issues relating to the rendering progress window/bar:
* Would be nice with a "cancel" button to kill the rendering
* The "remaining time" and "% finished" estimates given by flam3-render
and flam3-animate could be printed out here too, in addition to the
graphical progress bar.
* When animating, the two progress bars ("flames", "progress") are
confusing - I have only ever seen the "flames" bar measure the progress,
the "progress" one is always blank, what does it do?
* This may be a bug: when rendering animation to "Image sequence",
progress window does not autoclose even though the process has
stopped (on the window it says "writing movie to disk...", although there
is no movie to write and the images have all finished rendering).