BUG/TST: transform and filter on non-unique index, closes #4620
Merge pull request #5375 from danielballan/filter-nonunique

BUG/TST: transform and filter on non-unique index, closes #4620
BLD: dateutil-2.2 patch
Merge pull request #5411 from jreback/dateutil_fix

BLD: dateutil-2.2 patch