Easy SkyBlock

## v1.1.0

**New: Choose your island!**
The "Customize" button next to the Sky Block world type is now active. Click it when creating a new world to pick which island gets generated at spawn.

8 new islands added, on top of the original one:
- Frozen Isle
- Corrupted Mushroom Isle
- Desert Cave
- Farmer's Isle
- Forest Retreat
- Jungle Ruins
- Nether Rift
- Treetop Island

**Also new:**
- Custom islands are supported: drop your own `.nbt` structure file into `config/EasySkyBlock/` and it will show up in the island picker automatically.
- New config option `default_island_template` (server config) to set which island a dedicated server uses, since the picker screen only exists client-side.

No changes to existing worlds - this only affects newly created ones.