HostPeer: packet now can be sent
Fixed `EntityUpdatePacket` encoding
Quaternion operations
ngspades: some documentation on `EntityFlags`
ngspades: `World` class
ngspades: evaluation of entity trajectory
ngspades: created `PlayerEntity`
ngspades: add `GrenadeEntity`
ngspades: added classes for entity types
ngspades: computing matrix of entity
ngspades: support for entity listeners