Preparing for integration into the ECS
Former-commit-id: dbed63966f6c5e888a8b4f1c8f804c98d1c75458 [formerly cb6fa165276003b8d68932a95632025794557682]
Former-commit-id: ebce6b98f3e2ef8c5fc8d598b6cdc9e96fd0becc
Renamed ParticleEmitter to ParticleSystem
Added class ParticleEmitter
(First implementation, this will probably change)
Former-commit-id: a1f80db340983da5e85cedc974dd6b24a98e25b0
Switched back to defaulted operator=(ParticleEmitter&&) since it can't
throw exception anyway
Former-commit-id: 178b040a735ef01dcda21b45a317b6c534b5782e