3D floors are now updated in real time in visual mode when their control sector is sloped through the line slope action. Fixes #250.

* Adding check for missing activations on lines that have an activation-requiring action

* Adding skip check if the map isn't UDMF

* Oops, typo in name of check

Added: string/float user variables, //$UserDefaultValue <value> for specifying default user variable value

Fixed: GZDB wouldn't load plugins on certain paranoid systems due to plugin DLL's being "remote" and unsigned (reported by Lorenzo)

Added .iwad, .ipk3, .ipk7 extensions to recognized list (reported by someone somewhere some time ago...)

Fixed null reference in visual mode when trying to render a thing without a sector (reported by Ozymandias81)

Updated Unreal model loading to the fixed behavior in GZDoom - axes were remapped incorrectly (I blame Marisa_Kirisame)

Actually fixed vertex axes in Unreal models.  Fixed the order of rotations in MODELDEF Offsets (this was not releavent to Unreal issues)

Added simple Unreal model support;  Fixed numerous issues with normal handling;  Fixed outright invalid handling of AngleOffset/PitchOffset/RollOffset in MODELDEF

Fixed: GZDB was built against wrong SlimDX version (including 64-bit which was built against 32-bit SlimDX) - (reported by StrikerMan780, leodoom85, Rockstar Racoon)

Fixed (?): The new .NET 4.6.x JIT method inlining was fucking with GetCallingAssembly-based plugin detection

Fixed: on a second thought, let's just make FileImageReader fall back to guessed image if possible...