* Sample Signatures for put_enc and get_dec
* Implement put_enc and get_dec
* Implement ChainCodec in grin_chain
* Truncate src only on complete Blocks
* Truncate src only on complete Tip + Check Len
* Move BlockHeader Encoding to BlockHeaderCodec
* Define put_enc for store::Batch
* Replace BlockCodec and BlockHeaderCodec with generic BlockCodec<T>
* Implement Default for BlockCodec Manually
* Replace get_ser/put_ser with get_enc/get_dec for chain::ChainKVStore
* Remove Writeable/Readable for chain::Tip
* Add Tokio-io and Bytes to grin_p2p
* Additional Setup for Message enum + Msg{Encode,Decode} traits
* base msg ping pong encoding and test
* fill out msg-codec tests
* Implement Hand Encoding/Decoding
* msg-encode shake
* msg-encode getpeeraddr
* codec peer-addrs message, SockAddr struct wierdness
* header message codec
* msg encoding finished prelim
* Implement PeerCodec Encoding/Decoding
* Set PeerStore to use PeerCodec for Encoding/Decoding
* Add a DecIterator
* Prune PeerStore
* Replace Decoding and Encoding in handle_payload
* Prune Writeable/Readable methods in store::Store
* Remove Incomplete Frame Testing ( Not Nessesary right now )
* separate block and tx codec tests
* Refactor {Tx,Block}Codec Tests
