v4.4.0

• feature Added a way to add custom dimension in the action scope. #111
• feature Added automatic generation of the url property. #197
• improvement The PiwikTracker is now save to create in a background thread. #175
• improvement The Logger is now objc compatible. #185
• improvement Default example.com urls aren't generated anymore. #194
• improvement The Device and Applications structs are now public. #191