QOL Fixes and API Updates

[dshadowwolf]

1. Extend the base API so users can specify a new feature generator using the mixed binary and IMC method
2. Extend DimensionLogic so the feature-name can be passed in as a string
3. Remove the OreSpawn2 json format writer as it was only used during development
4. Remove the "getMaxHeight" and related calls from the SpawnEntry API (only used in the OS2 json writer)
5. simplify the code in DimensionLogic to add parameters and call down to a single point-of-failure
6. simplify SpawnEntry to only have the one constructor that is being used
7. Extend the FeatureRegistry to allow for registering by name&classpath instead of with a chunk of JSON.
8. Remove some code duplication in the FeatureRegistry and fix a potential bug when a feature has been loaded from _features.json and specified by a mod using the API
9. Add a command that causes the system to write-out the current configuration immediately