Practice now supports seperate theme layouts for entries with images and entries without, and it switches between them on the fly.

This was one of my major problems with the theming system.

The seperate layouts are, of course, completely optional, and it will default to the normal one if the image-specific one doesn't exist.

Even though I acomplished this change by keeping two scenes, views, widgets, etc around, I managed to decrease the number of variables stored in ParleyPracticeMainWindow; instead I made the entire class more functional (operating based on arguments instead of saved state), which is a win in my mind.

Flashcard mode can now use images, as per a bugzilla wish.
I still need to add some options, though.

The default theme was updated to use the new image specific theming.

Also, beginnings of work on the conjugation mode (yuck!).