RFC6587 et. al

[leodido]

This PR introduces several features and aspects:

• [x] Go modules
• [x] Interfaces
  • [x] syslog.Machines => parsers a byte slice
  • [x] syslog.Parsers => parsers supporting a stream
• [x] Streaming impl. of non-transparent framing for syslog transports, ie., RFC6587 (refs #16)
  • [x] Documentation
  • [ ] Error handling
• [x] Refactoring of existing RFC5424 to match interfaces and conventions
• [x] Refactoring of existing RFC5425 to match interfaces and conventions
• [x] CI setup

Note that I'll introduce BC with this PR.

[danielnelson]

Make sure to add a license to ragel-machinery.

[leodido]

Yup, done. Thanks @danielnelson