3.3.2 - bugfix update

I've just uploaded NEXXT studio 3.3.2. 
This time, there are three relatively minor bugfixes. If you don't need them there's no pressing reason to upgrade,
but doing so is at least a more stable experience.

• The menu action "save 2 subpalette sets in 1 file..." no longer saves the same set twice (which made it useless);
  but instead the 2 user-chosen objects, as intended. 
• The same action's dialog box now pops up at the center of workspace, rather than top-left corner.
• if in "tileswitch" / "mmc2" mode, drag-dropping tiles to swap them would cause a debug message to show. 
  It was supposed to be disabled in the release versions, and now is.