v0.2.0

CHANGES:

• Fix warnings from OCaml 4.08.1
• Monadic view about implementation of the state machine
• Handle let* syntax and add dependency with future_syntax
• Use at least dune.1.8.0
• Use emile instead mrmime about email address
• Support 8BITMIME
• Add some logs
• Rename Parser to Decoder
• Add Domain.compare
• Externalize some parsers/decoders
• Add Received encoder/decoder
• Functorize STARTTLS implementation
• Close properly a TLS connection
• Relax SMTP parser about End-Of-Line character (be compatible with gnutls-cli)
• Add tests
• Clean the distribution