Visual Mode: fixed a problem where offsetting the middle texture of double sided lines would not work under certain circumstances. Fixes #702

* Extended rendering options for drawing vertices
* Fixed vertex scale slider behaviour
* Force plot highlighted vertex in DragSectorsMode
* Moved ShouldRenderVertices property into the properties region
* made config file variable lower case to be in line with other config file variables

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

Snap selection to grid: fixed a problem that could cause a crash if geometry got removed by snapping it to the grid

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

OBJ Exporter: fixed a problem where the model path controls were disabled unless creation of MODELDEF was enabled. Fixes #692

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)

Event lines are now shown between things and map elements even if the thing doesn't have an action, but directly uses its args. Resolves #676

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

Improved associations between arbitrary UDMF fields (used by the Eternity Engine game configuration)

Find and Replace Mode: fixed a problem where linedef activation flags could not be found or replaced. Fixes #667

Drag Geometry Mode: floor and ceiling panning are now correctly preserved when dragging geometry. Fixes 648

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

Image Exporter: added option to chose between taking sector colors into account or not when exporting. Resolves #635

Image Exporter: fixed a bug where texture scales were not taken into account when exporting. Fixes #634

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)

Linedefs Mode: fixed a problem where flipping a highlighted linedef would also select the linedef. Fixes #571