Adds a random map generator tailored for the Dune 2000 mod,
D2kMapGenerator.
This map generator has some limitations compared to the RA/CnC
map generator (ExperimentalMapGenerator):
- Symmetry is far less accurate for non-trivial rotations.
- No circular map shapes.
- Unplayable regions are not obstructed and no symmetry corrections
are applied. This is partly due to mod limitations (e.g., no
decorative actors), but I've also considered it less important.
- Somewhat higher map generation failure rates, due to more extreme
play-space requirements.
In order to support the map generator, some additional features are
added to common map generation utilties:
- A "FromTemplates" MultiBrush collection shorthand.
- Path partitioning logic in Terraformer, use to split paths into
multiple TilingPaths with different segment types.
