Removed "Sectors Brightness Mode" action, because the mode itself was removed long ago...
Documentation: updated "DECORATE keys", "Things Settings" and "Linedefs Settings" pages.
Added, Game configurations: added "thingclasshelp" property. It's used to open a website when thing class name is clicked in the Thing Edit form.
Changed, "Raise/Lower sector to nearest" action: 3d floors are now taken into account when using the action on things.
Updated documentation.