• The zip release ships with sabre/vobject 2.0.5.
• BC Break: Moved the entire codebase to PHP namespaces.
• BC Break: Every backend package (CalDAV, CardDAV, Auth, Locks, Principals) now
  has consistent naming conventions. There's a BackendInterface, and an
  AbstractBackend class.
• BC Break: Changed a bunch of constructor signatures in the CalDAV package, to
  reduce dependencies on the ACL package.
• BC Break: Sabre_CalDAV_ISharedCalendar now also has a getShares method, so
  sharees can figure out who is also on a shared calendar.
• Added: Sabre_DAVACL_IPrincipalCollection interface, to advertise support for
  principal-property-search on any node.
• Added: Simple console script to fire up a fileserver in the current directory
  using PHP 5.4's built-in webserver.
• Added: Sharee's can now also read out the list of invites for a shared
  calendar.
• Added: The Proxy principal classes now both implement an interface, for
  greater flexiblity.