`getChunk` clarifications, `loadChunk` method

Based on @mikeprimm feedback on c34d11d0, renaming chunk coordinates in method sig to `cx`, etc.

Clarifying that `getChunk` returns null if it's not loaded.

Adding a `loadChunk` method, with optional bool to disable generating.
`HumanEntity` properly extendeds `LivingEntity`

We somehow missed this in the last PR.
Merge pull request #37 from prism/human-entity-extends

`HumanEntity` properly extendeds `LivingEntity`
Merge pull request #35 from prism/chunk-load

`getChunk` clarifications, `loadChunk` method
Add Voxel class

Got to merge that math branch…
Extracting base event "types" into interfaces

`BlockEvent` interface may be combined with any other event interface
rather than limiting child classes to being of one type.

Modifying state events to match the new structure.
Merge pull request #52 from prism/event-interfaces

Extracting base event "types" into interfaces
Add JSR 305 for @nullable support
Initial commit of Vector{3/2}{i/f/d} interfaces

Based on flow-math stuff
Document the Vector classes
Merge branch 'math'
We now have vector classes, use these instead of adding location classes
Cleanup/Enforce Game object on Event

Signed-off-by: Chris Sanders <zidane@outlook.com>
Add simple GameRegistry interface

Remove un-needed exception
Add getting an identifier by obj

Signed-off-by: Chris Sanders <zidane@outlook.com>
Add .checkstyle to .gitignore
Adding entity/player event interfaces

Adding a base event interface for both `Entity` and `Player`
Ignore .nb-gradle folder
Add collection of online players, max number of players, and a getPlayer method to `Game`
Add Damageable class with basic methods