@onlyworlds/sdk 4.16.0

Added

• epoch on the feed (keel 979eb0c). OwChangesPage.epoch and changesHead()'s
  epoch: a guest's view epoch (an integer), null for every other key. It moves when what a
  guest may see changes, even with head unchanged, so a poll walks when either head or
  epoch moved; nothing needs to read inside the cursor. changesHead() answers
  epoch: null from a keel without the field. Checked live on Moppetopia (the head read and a
  page both carry epoch: null). The wire gate now holds OwChangesPage and OwBulkResponse
  to keel's ChangesPage and BulkResult (keel #108), and failed on 4.15.0 for the missing
  epoch before this release.
  Published from tag v4.16.0; the workflow's read-back gave up before npm showed the
  version, so the tarball (shasum d08de22b) was read back by hand against a build of the tag.