Ideas for functions: normalise(), info_match_gap(), frames_since_match("X"), progress_between_matches("X")

[rewbs]

Add short cuts for:

• info_match_next("X")-info_match_last("X"), perhaps called info_match_gap("X")?
• f-info_match_last("Beep"), perhaps called frames_since_match("X") . It would then be sensible to add a frames_until_match("X") for completeness.
• frames_since_match("X")/info_match_gap("X") aka progress_between_matches("X") ?
• normalise(f, f_min, f_max)