Schematic API for structure loading

[avaerian]

Includes schematic file reading via NBT tags, fast structure placement via NMS, and support for WorldEdit as an alternative to the native NMS implementation

[avaerian]

Need to decouple Bukkit API from schematic parser/object archetypes for unit testing

[avaerian]

Work still needs to be done for the schematic API, such as:

• Loading metadata
• Placing entities (Fix entity placement for schematic API #28)
• Testing placing biomes (Fix biome placement for schematic API #27)
• API cleanup

Blocks are placed successfully in the world for the current version. Other versions will need to be supported, but that will fall under #21.

[avaerian]

Work that still needs to be done:

• Metadata loading (?)
• Better multi-version compatibility (write code that supports Sponge version 1, 2, and 3 respectively)
• Unit tests for Sponge schematic file format reading
• Test WorldEdit support
• Ensure biomes and entities work properly (create own test schematics) (Fix biome placement for schematic API #27, Fix entity placement for schematic API #28