Bug 1768: Calendar now retains the month on which the user was entering data.

Bug 1768: Calendar now retains the month on which the user was entering data.

If a user adds or edits a holiday, the calendar will now return to the month in which the user was working.  Also after an add or an edit, if the user selects another location, the calendar remains in the same month for which the add or edit took place.  The user sees a 'calendardate' parameter in the URL in the format that is chosen as the system preference.  If an invalid date is entered in the url, the current date is used.

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>
Signed-off-by: Henri-Damien LAURENT <henridamien.laurent@biblibre.com>