v0.13.1

Fixed

• git shuttle trace bind took a new branch for a merged one: a branch made at the tip of the base, which is the merge of somebody else's pull request,
  was given that merge and the commits of the other person, and they showed under its task in the graph and the Release tab. A branch with no commit
  of its own is now taken for a merged branch only when the merge names it ("Merge branch 'x'", "Merge pull request #1 from owner/x").