Agent: ReWrite

[MutableLoss]

This is due for a complete rewrite to better support the current options and future options, and setup a Marshal bridge between process and progress server.

Also want to move away from CLI to network API, with error handling.

[MutableLoss]

Rewrite is causing such a larger system change, that the project has changed to the new Frother: https://github.com/CGCookie/frother

[MutableLoss]

initial rewrite in 1.0.0, so Frother put on hold, but may revisit after barista-core 2.0.0.

[MutableLoss]

Note: The next iteration will need an error/message handler wrapping the rest of the agent, allowing any action to trigger a progress update, whereas now messages cannot be passed to the progress server until initialized in the BaristaRunner, due to the process forking concerns.

Consider re-writing in Rust for better asynchronous support, ability to compile agent to bytecode, and widen the scope of overall capability.

[MutableLoss]

To keep development time down, considering adding async support to Ruby with:
https://github.com/socketry/async