Changes are now tracked in `tilesToChange`.
(No more need for `tilesPrevious` and `tilesChanged`.)
Applied to full tiles instead of just height or texture.
- Empty (default) tiles will not be meshed,
they have to first be "drawn in" somehow
- Terrain data is stored in ... `TerrainData`
Can be exported to separate resource file
- Each chunks is stored in a `TerrainChunk`
- Height now stored as a short,
and `TileStep` can be adjusted
- Corners implements IEquatable
- Moved more code into editor plugin (GDScript)
- Moved remaining code back to Terrain script (C#)
- Editing controls themselves are now fully GDScript
- Plugin (GDScript) just calls `Terrain.EditorInput` (C#)
- Made some more changes and additions where sensible
copygirl