Event hooks ignore cancelled events by default

Add VoxelVolume super-implementation for World and Chunk; moved methods from World and Chunk. Add EntityUniverse super-implementation with methods to get Entities

Add Vector3i block and voxel getters to VoxelVolume

Add .checkstyle to .gitignore

Updating Block event with reference to Voxel

Updated `BlockEvent` with `Voxel getVoxel()` for block/position. I'm debating
renaming the events to `VoxelEvent` but that may be too different from
what devs are accustomed to.

Add cancel based methods to event base interface

Add ItemsStack interface, without any Inventory

Fixed javadoc, added missing @Overrides

Updating Block event with reference to Voxel

Updated `BlockEvent` with `Voxel getVoxel()` for block/position. I'm debating
renaming the events to `VoxelEvent` but that may be too different from
what devs are accustomed to.

Fixed javadoc, added missing @Overrides

I accidentally deleted this

I'm tired, I screwed up a few things

I'm tired, I screwed up a few things
Merge branch 'master' of https://github.com/zeuslightning125/SpongeAPI