Fixed a bug where flipping a line resulted in a crash, if its start vertex did not belong to any other line

- Re-enabled UDMF comments for element indices (should work with ZDBSP now)
@ Added test case for triangulation

Fixed a bug that crashes the SurfaceManager sometimes

- Increased spacing for image previews in the information panels so that long texture names can be fully displayed

- Better handling of missing UDMF TEXTMAP fields (Error now includes the element and index at which the field is missing and will not abort loading. Instead it will use a default value.)
- UDMF TEXTMAP now contains the indices of elements as comment next to the structure header.
- Thing cages in Visual Mode now also get the selection and highlight color so that a selection and highlight on things without sprite can also be seen.

Added default thing flag "dm" (1024) to game configurations so that things appear in deathmatch by default

- Progressive undo/redo system (much faster and up to 1000 undo/redo levels) Please note that several plugin functions and properties have changed.
- Some small optimizations in the classic 2D rendering (cached linedef flags, reduced some unneeded redrawing)

- Fixed a bug that allowed to use texture names longer than 8 characters, making the WAD file unusable after saving
@ added a texturenamelength config var. Setting it to higher than 8 may result in unexpected behaviour due to the speed optimizations relying on 8 char texture names and should not be changed for now.

@ added internal option to prevent automatic removal of unreferenced elements when other elements are removed

@ Added Create* functions in the MapSet that allows specifying the index (element at existing index will move to the end of the array instead of the newly created element).

@ Changed the MapSet to work with arrays instead of linkedlists. Because the index is now know for each element and can be retrieved in O(1) efficiency it has become a property (Index) for all map elements. GetIndexFor* functions have been removed. Get*ByIndex are now also of O(1) efficiency.

@ white texture has been moved to the DataManager and is now also available to plugins

Replacing can now be made undone

- Fixed some minor bugs in the choice of default drawing textures

Added variable "skyflatname" as a game configuration item. It is used to ignore false positives when checking for missing textures. Updated all the game config files to make use of this feature.