v0.4.1

bcommon v0.5.4 (from v0.5.1). The double-spend refusal found during the bbox review now applies here: arcade can answer ACCEPTED_BY_NETWORK for a transaction whose input another transaction already spent, which never mines. With a node configured (rpc, asset), the arcade: settlement leg now holds arcade's verdict to the node's view of the inputs, so create, status, rotate, retire, kill and pay refuse at once instead of waiting out their timeout and reporting the proof pending forever. Proof collection (publish -resume, the state token, funding trees, kill sweeps) already carried this check for free in the same upgrade.

• Also in this bump: v0.5.2 (registry documentation only, no code change) and v0.5.3 (a node answering in Extended Format, as a Teranode asset API does, no longer breaks paying from a coinbase coin).
• Docs: the README, architecture.md and overview.md now name the two sibling applications meant to close bfinger's open seams: bbox for payment notices, borg for handle certificates. Neither is adopted yet.
• No config or behaviour change without a node configured; funding = wallet and the pure async/no-node path are unaffected.