Fixed, Draw Lines/Rectangle/Circle/Curve modes: line length labels displayed incorrect length.

Changed, Drag Linedefs/Vertices/Sectors/Things modes: line length labels are now displayed the same way as in Draw modes.
Changed, Drag Linedefs/Vertices/Sectors/Things modes: "lock movement to cardinal directions" mode (Alt-Shift-Drag) now locks movement in 4 directions instead of 8 and doesn't snap map elements to nearest grid intersections when they are not aligned to it. 
Added, Visual mode, GZDoom, DECORATE: FORCEXYBILLBOARD flag is now supported.
Added, Visual mode, GLOOME, DECORATE: FLOORSPRITE, CEILSPRITE, WALLSPRITE, ROLLSPRITE and STICKTOPLANE flags are now supported (implementation is somewhat broken ATM and probably doesn't work the same way as in GLOOME, because Windows build with most these features is nowhere to be found...).
Fixed, Visual mode: in some cases Thing brightness was calculated incorrectly.
Updated ZDoom_DECORATE.cfg.