search_variables option to match variable subs

[OJWatson]

Session Info

search_variables looks for an exact match against a variable, e.g. hml35. If you are querying a wide dataset, e.g. HR files, then you will not match to say hml35_1. Should add an option to match sub_variables. This would impact the following in client.R

# now let's match
matched_rows <- na.omit(match(variables, out_desc$variable))