* Combine vector_like_traits::{insert,reserve}
and explain semantics better. This should make it more clear what
implementers need to do when implementing the vector_like_traits
concept.
* Update std::unordered_set vector_like_traits impl
This commit includes:
- The flatbuffers implementation
- A draft on how it should be used for network messages
- A serializer that can be used independently
What is missing:
- All root objects will need a file identifier
- Many special classes can not be serialized yet as the
corresponding traits are not yet implemented
- Object serialization can not yet be turned on (this will
need a network option)
