Ember data 0.13 fixes

Hi,

Here are some fixes that I found necessary to make the adapter work with Ember Data 0.13.  The RestAdapter now wraps call to ajax in RSVP, so I moved to same changes into the Tastypie adapter. There is also a fix for pagination (since) handling as the API had changed a little there.

To get the tests to work I had to wrap all calls to the store in Ember.run otherwise the ajax callback would not always be triggered before the result was checked. However, I see that in the tests for the RestAdapter in Ember Data that's not the case, so there may be a better way. However, after trying a lot of different ways this was the only way that worked for me.