Estate updates

- Ensure new estates start from 100
- Small text and info changes
Additional Region type updates

-  set combined type
- additional terrains
- Add max number of avatars for presets
- Set AllowLandResell & AllowLandJoinDivide flags correctly

Terrain updates
- Smarter input allowing prompting if required info is not supplied
- additional preset 'types' available  Grassland, Aquatic
- Initial blending for mainland regions