commit for holidays and news management.

commit for holidays and news management.

Contrib from Tümer Garip (from Turkey) :
* holiday :
in /tools/ the holiday.pl script let you define holidays (days where the library is closed), branch by branch. You can define 3 types of holidays :
- single day : only this day is closed
- repet weekly (like "sunday") : the day is holiday every week
- repet yearly (like "July, 4") : this day is closed every year.

You can also put exception :
- sunday is holiday, but "2006 March, 5th" the library will be open

The holidays are used for return date calculation : the return date is set to the next date where the library is open. A systempreference (useDaysMode) set ON (Calendar) or OFF (Normal) the calendar calculation.