Compassion Conference v3.0.0-alpha.0

• Reuse the single connection to the Colleague. See #462.
• Update LICENSEs for 2020. Closes #482.
• Convert depart to async/await. See #462.
• Restore join with backlog, send and reduce. See #462.
• Restore receive. See #462.
• Restore join. See #462.
• Test population race, Conference ready on exit. See #462.
• Restore bootstrap. See #462.
• Caret pin sibling dependencies of Conference. Closes #479.
• Remove Montonic dependency from Conference. Closes #478.
• Remove p-queue dependency. Closes #477.
• Upgrade avenue to 0.2.0-alpha.1. Closes #476.
• Upgrade cubbyhole to 3.0.0-alpha.2. Closes #475.
• Upgrade interrupt to 9.0.0-alpha.1. Closes #474.
• First pass at async/await conversion. See #462.
• Sketch of new conference object.
• Sketch of new API.
• Begin ES6 conversion.

Closes #484.