Update functions.R

[matmu]

1: select_() is deprecated as of dplyr 0.7.0. Please use select() instead. 2: arrange_() is deprecated as of dplyr 0.7.0. Please use arrange() instead. 3: filter_() is deprecated as of dplyr 0.7.0. Please use filter() instead. 4: group_by_() is deprecated as of dplyr 0.7.0. Please use group_by() instead.