Unite CanGroup with CanGroupBy, CanSort with CanSortBy (like CanNubBy already was)
CanDoBy -> CanDo
Makes Vector and UVector sortable
Adds mapM_ for ByteString and LByteString
Adds tests for ByteString's mapM_
A bit of a cleanup for tests
Adds CanSnoc, CanUnsnoc (with tests)
Adds tests for CanCons, CanUncons