tf_parseTakes the output of read_results and, inside of tf_parse,
extracts vertical jump round attempts (XXO etc) and associated row numbers
flash_round_attempts_parse(text)output of read_results with row numbers appended by
add_row_numbers
returns a data frame with split times and row numbers
flash_round_attempts_parse runs inside
flash_parse on the output of read_results with
row numbers from add_row_numbers