Updated ZDoom ACC to r3889.

UDMF: vertical offsets of a vertex can now be edited in Vertex Edit form and are shown in Vertex Info panel.
Bridge mode: when source sidedefs don't have upper/lower textures, their middle textures are used instead.

Merged Visual mode and GZDoom Visual mode into GZDB Visual mode. GZDoomEditing.dll is no longer required.

Rendering of (G)ZDoom rendering effects (slopes, 3D-floors etc.) can now be toggled in GZDoom Visual mode (default key is "Tab", action is Visual modes -> Toggle GZDoom rendering effects)

Added an option to enable DB2-style surface highlighting in Visual modes (when enabled, selected surfaces stay highlighted even if "Show Highlight" is set to OFF)

Added some boilerplate to UDMF map format reader. If a property value is Integer and expected property type is Float, a value will be casted to float. In other cases of type mismatch, the property will be ignored and a warning will be added to Errors and Warnings window.

Linedef and Sector Edit forms were saving default UDMF texture offsets (which led to increased map size).

TranslucentLine (208) action's "additive" property values were inverted.

Some more tweaks in ZDoom_misc.cfg

Added several UDMF properties to ZDoom configuration.

UDMF: UDMF texture offsets can now be edited in Sector and Linedef edit forms.
Floor and ceiling textures are now dragged properly in GZDoom Visual mode.

Floor and ceiling textures are now moved more predictably by arrow keys in GZDoom Visual mode.
Walls texture coordinates are always rounded when moved by arrow keys in Visual modes.
Linedef info panel: relative UDMF light values are now shown like this: 16 (128), which means "UDMF light value" ("total surface brightness (UDMF light value + sector brightness)")
Player is now spawned at camera height when testing from current location in Visual modes.
Focus is now properly restored after testing from current location in Visual modes.
Updated Heretic_sectors.cfg and Heretic_things.cfg as described here: http://www.doombuilder.com/forums/viewtopic.php?f=11&t=357
Changed sprites of artifacts in Hexen_things.cfg to proper ones.
Renamed Skulltag configs to Zandronum

Visual modes: selected objects are not highlighted when "Toggle highlight" (H key) option is set to off. 
Error Checks Mode: added linedef index to message text of all linedef-related errors.
UDMF: wall texture offsets are now rounded when user edits them via cursor keys or mouse dragging (because they are stored as integers anyway).

UDMF light editing in GZDoom Visual mode: sector brightness is changed instead of "lightceiling" property if targeted ceiling is part of 3D-floor.
UDMF Controls: increased precision of position and scale controls numeric inputs to 2 decimal places.
Sector/Linedef info panels: in some cases incorrect default values were shown for scale.
Sector/Linedef info panels: numbers are formatted more properly.

UDMF: changing brightness of a wall or ceiling in GZDoom Visual mode will change brightness of selected surface, not sector brightness.
Sector and Sidedef info panels show additional info if a map is in UDMF format.
Fixed: GZDoom menu panel wasn't updated when a map was opened via "recent files" item click.

Event lines for "event activators" (ActorMover, Camera and things with Thing_SetGoal special) are now drawn with different color.
Fixed a crash when a Thing with arguments is pasted in Visual modes.
Several other small fixes.
Fixed config error in ZDoom_things.cfg.
Fixed config error in ZDoom_ACS.cfg

Added toolbar button to toggle event lines on and off.

Order, in which patrol points and interpolation points are connected can now be shown in Things and Visual modes.

Lower and Upper portal icons were swapped.

Now only the root node of Folder/PK3/PK7 resource is expanded in Textures browser.

Actions and Effects can now be filtered (useful when you remember action/effect name, but don't remember it's number or category)

Fixed severe lags during Texture Browser opening when resource wad for current texture had lots of textures.
Texture groups weren't created properly in soma cases.
Added Monster/Hate Target sprite.

Added several new icons for ZDoom things