v0.3.0

What's Changed

• Negotiate the codec over a connection (2.1) by @timkpaine in #124
• Add a multi-tenant Hub with shared data structures and a merge seam by @timkpaine in #125
• Let apps register custom wire codecs by @timkpaine in #126
• SSE + Jupyter comm adapters; server-authoritative live receive by @timkpaine in #127

Full Changelog: v0.2.0...v0.3.0