Trivia window now appears immediately and uses loading cursor while
loading.

When starting the program, the frame now appears immediately and the
cursor changes to the loading cursor while hovering over the window.
Improvements to tear-away tabs.

Change to tear-away tab attach/detach mechanism and mouse poller for
more uniform performance. (Issue #69)

Tear-away tab is now a translucent image of the tab being separated.

Tabbed pane now removed from tabbed pane list when its parent frame is
closed.