Add IsEmpty to IReactiveList<T> and IReadOnlyReactiveList<T>.
Merge pull request #607 from reactiveui/isempty

Add IsEmpty to IReactiveList<T> and IReadOnlyReactiveList<T>.
Add ReactiveTableView
Merge pull request #608 from reactiveui/add_reactive_table_view

Add ReactiveTableView
Cast section info list to the matching IReactiveNotifyCollectionChanged<T>

Otherwise this always disables change notifications for section lists.
Merge pull request #609 from justin-factory/fix_commonreactivesource_cast

Cast section info list to the matching IReactiveNotifyCollectionChanged