moved name_to_rgn.r to ohicore; updated name_to_rgn.Rd

with instruction from @bbest:
#' FINISH: After any documentation edits or a new function file added, you'll need to do the following:
#' library(devtools)
#' document() # writes R documentation file (man/name_to_rgn.Rd), updates DESCRIPTION and NAMESPACE files of ohicore package
#' build() # to ensure works
#' install() # to ensure installs
#'
#' finally git it to github: commit, push, done.