Proof of concept for setting dismissed field for notifications table, to mark a notification that's already been viewed.
Intermediate commmit for proof of concept;
disables normal functioning of notif modal, but demonstrates setting of dismissed field for notification table;
next step is combining the two.
Added file notifDismiss.php as a require_once call -- for notifArticle, userCard, etc. Just append the notif_id to the url as a query.
Working version.
Some CSS tweaks.
Only create notifs modal if user logged in - SESSION[user_id] exits. Otherwise breaks landing screen.
Misc tweaks to working(?) notif modal.
Merge branch 'modalNotifPanes2' of https://github.com/elizuck/circulate into modalNotifPanes2

Conflicts:
	templates/header.php
Added badge to notifications icon in nav bar;
number is retrieved once per header.php load;
live updates to badge currently just JS decrement on client side, called when notification clicked has '.new' class;
this doesn't account for incoming notifications between page loads;
a better solution would be grabbing the number of rows in circulate.notifications table, with 'dismissed' set to '0'.