Functions for arbitrary time shift and for shifting from daylight saving to standard ("winter") time.
Utility funcion paste.path to paste strings as file path elements with separator "/".
Convenience and utility functions for time:

as.Date.ymd -- convert numeric year, month, day to Date object
first.day.of.next.month
last.day.of.month

make.t.range.week.of.month -- time range of week within a month; optional argument for last week in month to end this month or extend into next month