fix typos in readme

support contact sync messages

improve failed send model

support handling failed sends

add room and store

add contact struct

add max file size

fix message decrypting

protocol update: addresses are preceded by 1 byte length, not 4 bytes

protocol update: server sends the number of recipient keys, not length

support file transfers

fix broken message serialization

protocol update

* address wire format changed
* server-side timestamps removed
* when sending multiple copies, length is only prepended once

add MessageContent::from_bytes

remove rustfmt.toml

refactor

remove debug statement accidentally committed

refactor

add comment

add MessageContent::to_bytes to simplify hashing in clients