Just added tile.obj.
-A sort of shader has been added (only specular lighting)
-Models now support texture swapping
-Added castle obj and texture
-Added cannon obj and texture
-Automatically flips the z-axis on models when imported.
-Automatically flips the y-axis on uv coordinates when imported (it just
has to happen for some reason).
Merge remote-tracking branch 'origin/frontend-tile-clicking' into frontend-dev