Changelog:
- Store entity idx for component map as key. This allows reference
to the entity for related components in a system
- Modify systems to iterate over components instead following the
above change. This follows closer to the intended ECS architecture
Internal Changelog:
- Use data store similar to component map
- Add init and free for entities tag
- Use enum instead of char for tag
- Switch to use clang for compilation
- Add -Wall for compilation
En Yi