3D Floor Mode: fixed a bug with the "Detach all" and "Split all" that would create (and immediately delete) redundant control sectors

Draw Grid Mode: added option to to draw the slices relative to the origin of the drawing (so that you don't have to change the slice interpolation all the time)

Added the "nocount" UDMF thing flag (as "No completion count") that was added in GZDoom 4.4.0 to the ZDoom config. Fixes #422.

Added comments to code

Made sloping work more reliably with irregularly shaped sectors

3D floor mode: fixed a problem where splitting a 3D floor didn't work correctly when some selected sectors didn't belong to that 3D floor

Improved handling of changing input boxes in slope arching form

Texture sets now work with textures from a directory or PK3/PK7 (it matches against the short 8 character name)

Improved functionality

3D Floor Mode: fixed a bug that would not increment the sector tags correctly if a tag range is used

Fixed a bug where modifying a user_ ZScript variable through the custom properties tab would cause a crash. Fixes #420.

Edit Selection Mode: fixed a bug where the control sectors of sloped 3D floors were not updated correctly when one 3D floor was applied to multiple sectors

Fixed some more cases where UniValues were set to floats. Added throwing exceptions to the UniValue constructor (gasp!)

Removed lots of unnecessary casts to float of the Math methods. Also removed some other minor implicit casts

Edit Selection Mode: rotating sectors with plane equation slopes now works correctly if the sectors are not rectangular

Edit Selection Mode: slopes of 3D floor control sectors are now properly updated when moving/rotating sectors (only when not pasting)

Fixed an issue in Edit Selection Mode that could cause Out Of Memory exceptions with vertices that are slightly off grid in the 32 bit version