Visual Mode: added actions to lower and raise map elements by the current grid size (no defaults bound). Resolves #699

Visual Mode: fixed a problem that resulted in incorrect texture offsets when moving a texture by grid size, and the grid was a multiple of the texture size

GZDoom game configuration: added support for distinct upper/middle/lower sidedef brightness levels. Resolves #694

Visual Mode: added toggleable option to select all adjacent visual vertex slope handle when selecting a visual slope vertex handle. The action is called "Toggle Adjacent Visual Vertex Slope Selection"

Added classic rendering mode to closer emulate software renderer visuals in visual mode

Added "Orbit" and "Move Camera to Cursor" visual mode actions (not bound by default)

UDBScript: Exported the classes Linedef, Sector, Sidedef, Thing, and Vertex, so that they can be used with instanceof
UDBScript: Map class: the getSidedefsFromSelectedLinedefs() method now correctly only returns the Sidedefs of selected Linedefs in visual mode (and not also the highlighted one)
UDBScript: Map class: added a new getSidedefsFromSelectedOrHighlightedLinedefs() method as the equivalent to the other getSelectedOrHighlighted*() methods
UDBScript: Sector class: added new floorSelected, ceilingSelected, floorHighlighted, and ceilingHighlighted properties. Those are mostly useful in visual mode, since they always return true when the Sector is selected or highlighted in the classic modes. The properties are read-only
UDBScript: Sidedef class: added new upperSelected, middleSelected, lowerSelected, upperHighlighted, middleHighlighted, and lowerHighlighted properties. Those are mostly useful in visual mode, since they always return true when the parent Linedef is selected or highlighted in the classic modes. The properties are read-only
UDBScript: added new example to apply textures for floor/ceiling and upper/middle/lower texture for selected map elements
UDBScript: updated documentation

Added map scripting capabilities to UDB (#656). Documentation at https://biwa.github.io/udbscript-docs/

Visual Mode: fixed a bug where textures on 3D floors were not scaled correctly when using the upper/lower texture 3D floor flags. Fixes #640

Eternity Engine game configuration: it's again possible to set the floor and ceiling brightness independently from the sector brightness

Game configurations: added option to enable/disable GZDoom style distinct brightness for walls/ceilings/floors. Fixes #618

Visual Mode: added some safeguards against potential crashes that should never happen. Potentially fixes #614

Visual Mode: fixed a problem where highlighted visual slope handles were not highlighted anymore after clearing the selection

Visual Mode: fixed a bug where auto-aligning textures wouldn't work correctly in game configurations without support for local sidedef texture offsets, when short texture names were used, but the texture's source was a full texture name (i.e. from the /textures directory)

Resetting a slope in Sector Edit Form UDMF or with the Reset Slope action will not set the height to the z position at the center of the sector anymore, but to its original height

Visual Mode: fixed inaccuracies of when upper/lower textures are shown when sky rendering is enabled

Fixed a bug where pasting texture offsets in UDMF configurations without support for local sidedef texture offset (like the Eternity UDMF configuration) didn't work. Fixes #538

Using the "Reset plane slope" action now sets the floor or ceiling heights to the height of the plane at the sector's bounding box center

Added option for special handling of triangular sectors when doing visual sloping. When enabled it'll always select an opposite smart pivot handle. Enabled by default, can be disabled in Tools -> Preferences -> Editing -> Opposite side/vertex is smart pivot handle on triangular sectors

Fixed a bug where map elements could be selected multiple times when paint selecting in visual mode. Fixes #519. Fixes #520

Some refactoring regarding visual sloping

Using visual sloping to create a horizontal slope will now remove the slope and set the appropriate sector height instead
The Edit Sector dialog will not remove horizontal slopes anymore unless necessary

Visual Mode: fixed a problem where pasting a texture to a 3D floor sometimes didn't show the pasted texture immediately

Visual Mode: changed name from "GZDB Visual Mode" to simply "Visual Mode". The naming difference was for historical reason that doesn't apply anymore. Also reverted the mode icon to the original one

Visual Mode: fixed a bug where selected 3D floor tops/bottoms would appear to be selected after undo, but actually weren't selected anymore

Visual Mode: fixed a bug where the line slope things (9500 and 9501) would slope the same sector multiple times when multiple lines of the same sector were tagged to the thing. Fixes #491.