Removed one accidentally added virtual modifier.
Started to refactor TileRenderer:
- Removed RenderState from it, TileRenderer constructor takes only
BlockImages, WorldCache (and a render mode in the future) as parameters
- Rendermodes will be integrated soon(tm) again
Removed RenderState objects also from render modes.
Moved Rendermode base class, renamed it to RenderMode.
Started to rename some rendermode's to render_mode.