move .strptime into parse.R where it belongs
cosmetics in .select_formats
rewrite parse_hms
rewrite parse_dt to allow for formats (strptime) and orders (parse_date_time)
adjust and cleanup parser tests
adjust front end hms for new C parser
add fast_strptime and adjust everything else
fix small bug in parser
new tests for fast_strptime and parse_date_time2