Ability to change terrain mesh proceduraly

[AlemSnyder]

When one is in the game there needs to be a way to add/remove tiles.

• [x] Mesh rendering is done by chunks, and not by all the terrain at once
• [x] Change tile function that also updates the mesh of the chunk.
• [x] Mesh change changes on GPU memory.

[AlemSnyder]

This is done when mesh_edit is merged.