Probably fixed probable I/O race condition when loading images.
Fixed Visual mode stuttering due to floating point precision degradation when running the editor for several days without restarting (internal timer is now reset when saving the map or creating a new one).
Fixed, Nodes Viewer, cosmetic: Nodes Viewer window position was reset after pressing the "Rebuild Nodes" button.
Added Eternity Game configurations by printz.
Updated ZDoom_ACS.cfg (CheckClass).
Updated ZDoom ACC (CheckClass).
Added, Sound Environments mode: current sound environment is now highlighted (can be toggled using "Toggle Highlight" action).
Added: Tag selectors now have up/down buttons.
Fixed, Sound Environments mode: sound environments were not updated after performing Undo/Redo actions.
Fixed, Sound Propagation mode: sound zones were not updated after performing Undo/Redo actions.
Internal: moved "Toggle Highlight" action to the core, also changed it's category to "View".
Internal: "Toggle Highlight" action state is now saved in the Program configuration.
Updated ZDoom_DECORATE.cfg (GetZAt).
Updated ZDoom_linedefs.cfg (Sector_SetPortal args).
Changed, Classic modes: bigger Thing arrows are now rendered when thing sprite rendering is skipped.
Changed, Classic modes: when "Fixed Things Scale" option is enabled, thing size stays at 2x scale instead of 1x when extra bounding box is rendered.
Added Preferences -> Appearance -> "Things transparency (Things mode)" slider.
Renamed Preferences -> Appearance -> "Things transparency" to "Things transparency (other modes)".
Externalized thing bounding box and arrow texture, used to render things in Classic modes (Textures/ThingTexture2D.png).
Updated ZDoom_DECORATE.cfg (A_SetUserVarFloat, A_SetUserArrayFloat).
Added Preferences -> Appearance -> "Hidden Things transparency" slider. It controls transparency of Things hidden by Things filter in Things mode, of all things :)
Changed, cosmetic: elapsed time is now displayed after resources loading finishes.
Changed, internal: changed Clock.CurrentTime type to long.
Fixed, Tag Statistics window: in some cases the map view was not updated after selecting items in Sectors/Linedefs/Things columns.
Fixed, cosmetic: Draw Curve mode icon was missing a shadow.
