LP#1320048: correctly display closures in the closed dates editor

This patch fixes a problem introduced by the patch for bug 1187035
that caused the closed dates editor to display all closures as if
they started and ended at the current time.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Jason Stephenson <jstephenson@mvlc.org>
LP#1320048: remove last use of Date.W3CDTF() from closed dates editor

To test, verify that the closed dates editor continues to
function normally, i.e.,

* single all-day closures can be added
* a multi-day closing can be added
* one can set a "detailed closing" with a custom start
  time and end time
* existing closures are display properly

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Jason Stephenson <jstephenson@mvlc.org>
LP#1320048: remove the Date.W3CDTF() JavaScript module

With the closed dates editor now using util.date, and
no other active use of Date.W3CDTF() going on, it can go.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Jason Stephenson <jstephenson@mvlc.org>