WebSearch: SPIRES date math search fixes
- Fixes treatment of the first day of the month in SPIRES date queries like "find date 1976-04-01 and t dog". (closes #431)
- Fixes "this week" and "last week" date search functionality.
- Accepts two digits for year search so that users can type 78 instead of 1978. (closes #948)
Reviewed-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>