Fixed a crash caused by loading dialog...

...instances being created when the previous one hasn't been disposed of
yet.
Fixed disposed controllers being selectable...

...added getFollowOffsetX/Y methods to AbstractController,
minor tweaks
Moved gibs to a container class...

...so that instead of each gib having redundant props that aren't even
visible most of the time, the props are being reused to display and
modify the currently selected gib's data.