Remove distiction between "point" and "solid" entities: unify them.
|Reported by:||Carsten||Owned by:|
The distinction between "point" and "solid" entities should be removed: both types of entity should be unified into a single entity type that is capable of both.
- This might also be the natural conclusion should we decide, following #125, to introduce a component system for entities as well.
- As a welcome side effect, the func_wall entity class becomes redundant and should be removed as well.