Add sashay() and shantay(), for funsies

[svmiller]

A la: https://twitter.com/connor_morozumi/status/1329780278701789184

The package already imports dplyr, so perhaps using sashay() as a wrapper for something like dplyr::select(-foo, -bar) might be dumb fun. shantay() could be a wrapper for dplyr::select(foo, bar).