Changed: when entering Visual mode, the camera is no longer positioned at...

Changed: when entering Visual mode, the camera is no longer positioned at "Visual Mode camera" thing when "Sync camera position between 2D and 3D mode" setting is enabled.
Changed: Visplane Explorer plugin is now initialized only in Doom/Hexen map formats.
Fixed, Visual mode: thing cages were not rendered when things didn't have a sprite.
Fixed, Internal, DB2 bug: Plug.Dispose() was never called.