0.0.8H - Level Properties handles Texture.

+ Level Properties gets/sets Textures.
Every time the texture is edited, all of the tiles have their texture
changed, and the rendertexture redraws them all again.

! TileSelections boundary selection bug still in.
! Still no WorldMap saving.
! The ordinary Level class for the game needs updating. Clean-up and
affirm differences between ELevel and Level.