Join functions keep attributes (e.g. time zone information) from the
  left argument for `POSIXct` and `Date` objects (#819).
Correct vignette titles
Merge branch 'master' of github.com:hadley/dplyr
expanded error msg about unsupported attributes
test for previous commit
test for previous commit
test for previous commit
Add revdep checks
Notify failures
Merge branch 'master' of github.com:hadley/dplyr