Enhance time unit features

There is some ambiguity with time units (specifically around processor properties). Two features which I think should be added:

• Currently only whole numbers are parsed correctly. For example, 10 milliseconds and 0.010 seconds are functionally equivalent, but only the former will be parsed. This is due to the regex used in StandardValidators.TIME_PERIOD_VALIDATOR which relies on FormatUtils.TIME_DURATION_REGEX (see below). Decimal amounts should be parsed
• The enumerated time units are nanoseconds, milliseconds, seconds, minutes, hours, days, weeks. While I don't intend to extend this to "millennia", etc. as every unit including and above months would be ambiguous, microseconds seems like a valid and missing unit

Definition of FormatUtils.TIME_DURATION_REGEX:

    public static final String TIME_DURATION_REGEX = "(\\d+)\\s*(" + VALID_TIME_UNITS + ")";
    public static final Pattern TIME_DURATION_PATTERN = Pattern.compile(TIME_DURATION_REGEX);