Ko reference fix

There was multiple problem in your code in question: http://stackoverflow.com/questions/19428485/durandal-app-not-reflecting-changes-in-view-model

First:
 - Durandal 2.0.0 is using no Knockout through requrejs. (The documentation is not updated) so there is no need to explicitly reference it because it can lead to strange error
- your this handling contained some error so you have created properties on the global window object.