Communicate with plugins via stdin & stdout

The main terry executable will communicate with language-specific and scheduler-specific plugins sending text-based messages to their stdin and reading analogous messages from their stdout.

Context

At the moment of writing this document, it isn't yet clear in what programming language to write terry. Anyway, I believe it to be important to ensure that plugins for terry must be language agnostic.

Decision

criteria:
  language-agnostic:
    title: Language Agnostic
  ease-of-debug:
    title: Debuggability

alternatives:
  - title: socket-based communication
    language-agnostic: yes
    ease-of-debug: 3
  - title: stdin/stdout communication
    language-agnostic: yes
    ease-of-debug: 1