Magic Cube

Beginnings of support for actual patterns!

Remember state of the dialog.

Improve the upper_text.

Improve the 'About' dialog.

Prettier spinner.

Improve the Pattern data: unique names, more even splitting into categories.

Minor.

Progress with Pretty Patterns.

Re-add the Pattern dialog, but attach it to the Pattern uistate this time.
The idea to do away with the dialog proves impossible - we'd have to resize the top bar, which causes very unpleasant flashes.

Minor