* Added to the F3 Debug Overlay is a "Texture:" label that counts the number
of textures currently loaded by the (SDL2) render engine.
* Added Teardown() functions to Level, Doodad and the Chunker they both use
to free up SDL2 textures for all their cached graphics.
* The Canvas.Destroy() function now cleans up all textures that the Canvas
is responsible for: calling the Teardown() of the Level or Doodad, calling
Destroy() on all level actors, and cleaning up Wallpaper textures.
* The Destroy() method of the game's various Scenes will properly Destroy()
their canvases to clean up when transitioning to another scene. The
MainScene, MenuScene, EditorScene and PlayScene.
* Fix the sprites package to actually cache the ui.Image widgets. The game
has very few sprites so no need to free them just yet.
Some tricky places that were leaking textures have been cleaned up:
* Canvas.InstallActors() destroys the canvases of existing actors before it
reinitializes the list and installs the replacements.
* The DraggableActor when the user is dragging an actor around their level
cleans up the blueprint masked drag/drop actor before nulling it out.
Misc changes:
* The player character cheats during Play Mode will immediately swap out the
player character on the current level.
* Properly call the Close() function instead of Hide() to dismiss popup
windows. The Close() function itself calls Hide() but also triggers
WindowClose event handlers. The Doodad Dropper subscribes to its close
event to free textures for all its doodad canvases.