Added action to change the index of linedefs, things, sectors, and vertices. Can be accessed through a shortcut (not bound by default) or the menu of the respective mode (#903)

- A new "Show Textures" option up on the top bar, which draws any sector not flagged to be hidden on the textured automap
- Holding Shift will highlight sectors instead of lines
- Left-clicking on a highlighted sector will toggle the "Not shown on textured automap" flag
- Textures will be shown when Shift is held down even if the "Show Textures" toggle is off

Edit Selection Mode: fixed a problem where floor and ceiling textures were unintentionally scaled in UDMF when resizing the selection. Fixes #873

Nodes Viewer Mode: fixed a problem where trying to engage the mode with an empty map could crash. Fixes #857

Map Analysis Mode: fixed a problem where lines with fractional vertex positions could erroneously be reported as overlapping

Stair Sector Builder Mode: fixed an issue where the number of sectors and the sector depth was not loaded correctly when a default prefab was set. Fixes #847

Nodes Viewer Mode: a crash that could happen when the nodes header was interpreted as an UTF-8 value should be fixed for good now (#827)

UDBScript: setting an UDMF string field to an empty string will not remove the field anymore, but actually set it to an empty string

Disabled visual sloping for game configurations that do not support plane equation slopes. Fixes #828
Added toasts for visual sloping events

Improved UDBScript to version 5:

- Added Plane class
- Added BlockMap, BlockEntry, and BlackMapQueryResult classes
- Sector class
  - Added getLabelPositions method to get the position of sector labels (where tags, effects etc. are displayed)
- Added support for JavaScript BigInt for UDMF fields. This means it's not necessary anymore to use UniValue to assign integers to new UDMF fields. Instead it can be done like this: sector.fields.my_int_field = 1n;
- Added type information file (udbscript.d.ts)

Behavior can be configured in the "Toasts" tab in the preferences.

3D Floor Mode: added support for UDMF game configurations without support for sectors with multiple tags (i.e. Zandronum)

Tag Range plugin: fixed a problem where the new tags were not displayed in Sectors Mode when selection numbering was disabled. Fixes #795

Sectors Mode: fixed a regression where sector labels were not updated after editing sectors. Fixes #793