[mythtv] MythGallery Enhancement- Ability to specify transition durration.

[Mark Dobossy]

I have made a patch, and submitted a ticket:
http://svn.mythtv.org/trac/ticket/1876

If you use MythGallery, please give it a shot and let me know what you
think!  It adds an option in the MythGallery setup screen to specify
the durration of the transition for OpenGL transitions in a slideshow.
 It then scales the transition to take the specified number of
seconds.  I tested it, and it seems to work well, but am looking for
feedback.

This is part of the code that I am using to add the Ken Burns effect
to slideshows.  Hopefully I will have a Ken Burns patch in the next
week or two.

-Mark