Update Level.cs

Added support for the last few missing settings in Anvil worlds. This includes:
- generatorVersion
- generatorOptions
- initialized
- allowCommands
- DayTime
- GameRules:
  - commandBlockOutput
  - doFireTick
  - doMobLoot
  - doMobSpawning
  - doTileDrops
  - keepInventory
  - mobGriefing
Update Level.cs

Removed SchemaOptions.OPTIONAL from all sub nodes of GameRules. As far as I can see GameRules is mandatory
Merge pull request #13 from snoopen/patch-1

Update Level.cs
Apparently I forgot to commit this?
Merge branch 'master' of github.com:jaquadro/Substrate
Any new fields (including compound subfields) need to be either OPTIONAL or CREATE_ON_MISSING.  Only entries that are part of a compound when it is first introduced need not be optional.
If exposing boolean properties, it's simpler to also keep the internal representation boolean.
Sort regions before enumerating (contrib. by Sukasa)
Update block and item info to 1.6
Added in proper Biome access support.  Alpha Chunks are stubbed to return NULL for the biome manager.
Merge pull request #16 from Sukasa/master

Add support for accessing Biome information stored in an Anvil chunk
Add appropriate checks for interface set-operations on BlockManager.  Fixes #17
Adressed warnings, added Visual studio gitignore file, changed to Framework to 3.5