Removed ComboBoxCaseSensitive since it was a not-really-working hack, and all the names it was going to be used on have become CaseInsensitiveString's anyway, thus negating the issue.
Get rid of PonyLoader object on Main form, instead use ThreadPool and IdleWorker to get the job done.
Let DesktopPonyAnimator handle initializing and re-initializing interactions as needed. Main no longer needs to.
Move SpriteDebugForm startup into DesktopPonyAnimator class (which is correct). PonyAnimator was starting the shared instance instead.
Added a preview window to the new editor, using a shared instance per form as recreating the interface would get expensive.