• Note: This version is forked from version 1.0.5, so release dates may be out
  of order.
• Added: CalDAV - RFC 4791
• Removed: Sabre_PHP_Exception. PHP has a built-in ErrorException for this.
• Added: PDO authentication backend.
• Added: Example sql for auth, caldav, locks for sqlite.
• Added: Sabre_DAV_Browser_GuessContentType plugin
• Changed: Authentication plugin refactored, making it possible to implement
  non-digest authentication.
• Fixed: Better error display in browser plugin.
• Added: Support for {DAV:}supported-report-set
• Added: XML utility class with helper functions for the WebDAV protocol.
• Added: Tons of unittests
• Added: PrincipalCollection and Principal classes
• Added: Sabre_DAV_Server::getProperties for easy property retrieval
• Changed: {DAV:}resourceType defaults to 0
• Changed: Any non-null resourceType now gets a / appended to the href value.
  Before this was just for {DAV:}collection's, but this is now also the case for
  for example {DAV:}principal.
• Changed: The Href property class can now optionally create non-relative uri's.
• Changed: Sabre_HTTP_Response now returns false if headers are already sent and
  header-methods are called.
• Fixed: Issue 19: HEAD requests on Collections
• Fixed: Issue 21: Typo in Sabre_DAV_Property_Response
• Fixed: Issue 18: Doesn't work with Evolution Contacts