Improves behavior of data sources on iOS 10. ReactiveX#999

Author: kzaher

RxCocoa/iOS/Proxies/RxCollectionViewDataSourceProxy.swift

@@ -20,7 +20,7 @@ class CollectionViewDataSourceNotSet
     : NSObject
     , UICollectionViewDataSource {
     func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
-        rxAbstractMethodWithMessage(dataSourceNotSet)
+        return 0
     }
 
     // The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:

RxCocoa/iOS/Proxies/RxTableViewDataSourceProxy.swift

@@ -20,11 +20,11 @@ class TableViewDataSourceNotSet
     : NSObject
     , UITableViewDataSource {
     func numberOfSectionsInTableView(tableView: UITableView) -> Int {
-        rxAbstractMethodWithMessage(dataSourceNotSet)
+        return 0
     }
 
     func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        rxAbstractMethodWithMessage(dataSourceNotSet)
+        return 0
     }
 
     func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {