replace with quick-protobuf

[yoshuawuyts]

pure Rust & faster, means we can use it inside WASM / port it more easily https://github.com/tafia/quick-protobuf

[yoshuawuyts]

This one looks good too! https://github.com/danburkert/prost

[bltavares]

Given that https://github.com/stepancheg/rust-protobuf/ is written in pure rust according to the README, is there still a reason to change the lib?

[Frando]

One thing is that the structs created by quick-protobuf (or Prost, but that uses protoc still) are much leaner and lighter than the ones created by rust-protobuf.

[bltavares]

While the crate now uses a pure-rust lib, there is still an opportunity to improve the generated crates. I'll keep the issue opened.