Release 0.3.1

This fixes an issue with npm where 0.3.0 was not available for install.
Merge to remove dangling head

When I republished 0.3.1 to fix an issue, I must not have pushed the
master branch ref, but I did push the commit and the tag, so it wasn't
in history. While it isn't an important change, I figure it should be
merged in to avoid any future confusion.