Unity: new tile resources and no mipmapping
Unity: added and implemented a Random class

Specifically Xor128
Unity: added and implemented Vector3i, Vector2i and Size2i
Unity: proper World, WorldChunk, TileCamera implementations

* The World class holds and generates WorldChunks which in turn contain
tiles. A World has an initial seed, which in turn is used to
(deterministically) generate seeds for each WorldChunk. Once a
WorldChunk is generated it will be saved in its entirety to disk, and
loaded when need-be
* WorldChunks are procedurally generated from an initial seed.
Currently they know nothing about other WorldChunks; something which
will need to be addressed when it comes to things like generating
fringes at borders
* TileCameras can be added to Worlds and determine what chunks are
generated/loaded into memory
* Also includes the Recti struct which should be relocated to some
other place
Unity: updated MeshTiles implementation

* Uses two triangles per tiles
* Uses a texture atlas and a single material
* Includes callbacks for what texture index to use for a given tile and
a texture rect modification callback (for flipping x/y)
* Also includes updated TileMaterial
Unity: added and implemented WorldVisualizer

* Provides a visual representation of a World by creating MeshTiles
instances
Unity: added and implemented GameController

* Basically a test script which creates a World and assigns that to a
WorldVisualizer
* Includes a TileCamera which can be modified by its parameters in the
inspector
Unity: updated scenes + misc