1.8.0

• release tags are now prefixed by side: the github release is tagged
  dist/vX.Y.Z instead of vX.Y.Z, and the source commit that produced it is
  tagged src/vX.Y.Z and pushed. previously only the release branch was
  tagged, so a version's source was reachable only by reading CHANGELOG and
  guessing at commits.
• the prefixes are on both sides on purpose. tagging only the source as
  src/... and leaving the release bare would mean a repo where v1.2.3 is a
  build and v1.2.4 is a source, with nothing in either name to say which.
• existing bare vX.Y.Z tags are left alone - renaming them would break
  published release links and anything already installed against them. the
  rule is simply that a bare tag predates this change and is a build.
• note for github:owner/repo#dist/v1.2.3 installs: verified that npm keeps
  the slashed committish intact and that codeload serves the encoded form.