- MFH: Fixed weekdays adding/subtracting algorithm.

- MFH: Fixed weekdays adding/subtracting algorithm.
- MFH: Fixed some ambiguities in the date parser.
- MFH: Fixed bug #45529 (new DateTimeZone() and date_create()->getTimezone()
  behave different).
- MFH: Fixed bug #43452 (strings containing a weekday, or a number plus weekday
  behaved incorrect of the current day-of-week was the same as the one in the
  phrase).
- MFH: Fixed a bug with the YYYY-MM format not resetting the day correctly.
- MFH: Fixed a bug in the DateTime->modify() methods, it would not use the
  advanced relative time strings.
- MFH: Fixed a segfault - simply a forgotten return;