Show closed dates in date picker

[Benjamin Kalish]

Wishlist! The date picker (showed when editing the shelf expire time, due dates, etc.) should show dates on which the library is closed by, for example dimming these dates or showing them in a different form of the typeface (perhaps italics). Mouseover text should also indicate that the library is closed on that date.

This will help avoid errors in which staff mistakenly extend a due date or shelf expiration date onto a holiday.