Move to RustCrypto and implement stream cipher traits?

See [stream-cipher](https://docs.rs/stream-cipher/0.2.0/stream_cipher/) crate. You have read-write access to [RustCrypto/stream-ciphers](https://github.com/RustCrypto/stream-ciphers) repository,

Also It would be nice if you'll share the crate access either with me, or with RustCrypto:stream-ciphers team, so in future it will be possible to publish updates even if you will not be around.