Fix for Mantis #24929.

rtl/sysutils/datih.inc:
  + add StrToDate overload which allows passing of specific TFormatSettings parameter
rtl/sysutils/dati.inc:
  * implement new StrToDate overload by calling IntStrToDate similar to StrToTime


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@25392 3ad0048d-3df7-0310-abae-a5850022a9f2