This makes demos render correctly on hiDPI displays,
while also demonstrating how to handle multiple resolutions.
The 3D in 2D demo now uses "3D No-Effects" for the 3D viewport,
which is faster to render. Thanks to this, 4× MSAA is now enabled
for a better result.
The background loading demo now uses mipmaps for better-looking images.
The material testers demo now samples mouse input in a
resolution-independent manner when panning.
Default clear colors were also changed in some projects for visual
consistency with the project's theme.
1. Renamed `CELL_TYPES` enums to `CellType`
2. Fixed references, old: `turn_combat_system/actors/Actor.gd`, new: `turn_combat/combatants/Combatant.gd`
3. Fixed references, old: `turn_combat_system/actors/health/Health.tscn`, new: `turn_combat/combatants/health/Health.tscn`
4. Fixed bug in `grid_movement/pawns/Actor.gd` extending lowercase `pawn.gd`; changed to `Pawn.gd`
5. Renamed lowercase `grid_movement/pawns/actor.gd` to capital `Actor.gd` for consistency
6. Fixed some unused local variables warnings
Other changes are from engine, after opening and saving all scenes.
