Breaking dependence on NotificationTypes enum.

Changed from a parallel notification system to one that rewrites sections
of the existing notification system.

Alterations to the Notifications table to supply more information about
the structure of any given notification.

New notifications can now be added via XML and added via Lua (and inside
the DLL).

Those notifications can have their messages and summaries defined via XML.

Notifications successfully rebroadcast on game load and still center the
camera properly when given x,y coordinates.

Added a new Lua event, PlayerCanDismissNotification(int playerID, int
notificationID, int notificationLookupIndex), used to control the
dismissing of notifications from Lua.