data using a thread-safe collection. Some NPEs fixed. More data protection in tiled integration functions (better state checking, backup tiled-made file before saving ATCS-made data). jardesc file added for convenience.
opening in Tiled, and attempts to save a backup of the externally-modified one when saving in ATCS if necessary.
you have tools to help selecting external tools to bview/edit images and tmx maps. Still rough.
