Xamarin client updates

Because of the using blocks, these one line methods need the async
modifier so that the that async state machiner is created. Otherwise, if
the method does not complete synchronously, the connection is closed
before the database has returned its results.

The methods that return collections should return
Task<IEnumerable<dynamic>> not Task<dynamic>

Minor fixes to Xamarin client.

Bumped Forms version from 2.3.3 to 2.3.4 + more tidy up.

Consolidated Json.NET to 9.0.1.
Updated Microsoft.NetCore.UniversalWindowsPlatform to 5.3.3.
Added Autofac to iOS and Droid app projects.

Instead to register EventHandlers we register Func<EventHandlers> which solves scope problems (having transient/scoped objects owned by singletons)

Revert "Fix API signatures for collections"

Fix API signatures for collections

The methods that return collections should return
Task<IEnumerable<dynamic>> not Task<dynamic>

Unit tests

Cleaning up and fixing typos