Fixing what I think is a bug with property updates on fetch requests

I have been writing a AFIncremental store to use against CouchDB.

I was having issues with a TableView getting property updates on objects.

The context being used for fetch requests were being nil'ed out and never firing change updates on properties.

On large imports this can wreak havoc on the disk. For small imports things were great and the UI thread doesnt get blocked.

It still needs some optimization but property update changes are now properly firing.