3.0.0-beta2

• A node's properties should not overwrite properties that were already set.
• Some uris were not correctly encoded in notifications.
• The zip release ships with sabre/vobject 3.4.4,
  sabre/http 4.0.0, sabre/event 2.0.2,
  sabre/uri 1.0.1 and sabre/xml 1.0.0.