Fixed occasional TreeView flickering in Edit Things window, Browse Action window and Tag Explorer panel.
Updated Thing category icons in the Edit Things window. They now have "opened" and "closed" states.
Internal: added BufferedTreeView to the core controls.
Updated ZDoom game configurations (sector crush mode).
Updated ZDoom ACC.
Fixed, Map Analysis mode: fixed a crash when trying to dissolve an invalid sector when one of it's linedefs referenced it on the both sides.
Fixed, Sectors mode: fixed incorrect undo description when deleting sectors.
Internal: joined declaration and assignment of some more variables.
Sound Environment mode: added "Show nodes with warnings only" checkbox to the panel.
Sound Environment mode: somewhat increased sound environment update speed by updating the list after all sound environments are updated.
Sound Environment mode: the list now scrolls to show highlighted sound environment.
Sound Environment mode: sound environments can now be (de)selected. Selecting a sound environment stops highlighting sound environments / scrolling the list when moving the mouse.
Changes since 5bf51d0:
Large scale cleanup & refactoring.
Sound Propagation Mode: you can now click on doublesided linedefs to toggle sound blocking flag.
Sound Environment Mode: you can now click on doublesided linedefs to toggle sound zone boundary flag.
Sound Propagation Mode: reimplemented the highlighting of non-deaf things. Things are now highlighted using selection color.
Removed "Show tooltips" checkbox. Tooltips are now always enabled.
Fixed, Sound Environment Mode: thing tooltip about multiple active sound environment things was shown even when there was only one active sound environment thing.
Fixed, Sound Environment Mode: "Configure colors" toolbar button was not working because of missing action.
Fixed, cosmetic: "Configure colors" toolbar icon was missing a tooltip.
Fixed, cosmetic: display was not redrawn after changing colors using "Color configuration" window.
