Improving async await calls

Changing all async void calls that are not UI event methods to return Task.
This will help ensure that exceptions are handled on the UI context.
Merge pull request #2 from bholmes/ermau-changes

Improving async await calls
Merge remote-tracking branch 'origin/master' into JonPChange

Conflicts:
	Xamarin.Android/ZUMOAPPNAME/ToDoItemAdapter.cs