* Refactored routines for parsing/writing standard date/time strings
(RFC822 and XML xs:dateTime formats) into 'lib/rddatetime.[cpp|h].
* Removed the 'RDWebDateTime()', 'RDGetWebDateTime()',
'RDGetWebDate()', 'RDGetWebTime()', 'RDGetWebMonth()',
'RDXmlDate()', 'RDXmlTime()', 'RDXmlDateTime()' and
'RDXmlTimeZoneSuffix()' functions from 'lib/rdweb.[cpp|h].
* Added a 'dateparse_test' test harness.
