Delete useless textures and models

- LavaGolem_diffuse.png
- LavaGolem_emit.png
- LavaGolem_spec.png
- LavaGolem_normal.png
- Stool_col.png
- Stool_nor.png
- Stool_spec.png
- Stool.material
- Table.material
- Table_col.png
- Table_nor.png
- Table_spec.png
- trainingpole-tex-nm.png
- trainingpole-tex.png
- Trainingpole.material
- Stool.mesh
- Table.mesh
- TrainingPole.mesh
- Chair.material
- Shelf.material
- Chair_col.png
- Chair_nor.png
- Chair_spec.png
- Shelf_col.png
- Shelf_nor.png
- Shelf_spec.png
- Chair.mesh
- Shelf.mesh
Adapted the CREDITS file to latest changes.