auto merge of #2275 : gsingh93/servo/master, r=Ms2ger

Timestamp should return the time the event was created, not 0. This fixes three test cases in dom/events/Event-constructors.html. This is my first pull request, let me know if there are any issues.
Use new attributes syntax in properties.rs
auto merge of #2279 : Manishearth/servo/patch-3, r=jdm
WIP: Add Performance object to Window