Initial commit of working Xamarin Android provider.
Filled in remaining message information.
Initial commit of Xamarin IOS provider.
Added AssmblyInfo for Xamarin.iOS provider.
Added most iOS environment variables.
Xamarin provider name in RaygunClientMessage.
Some tidy ups.
Added Xamarin.Android provider to the NuGet package.

Updated NuGet.exe.
Also set minimum NuGet version to 2.5 in order to detect mono apps.
Simplifying the Raygun constructor for Android.
When not connected to the internet, store exception messages and send later when possible.
No longer need to pass the Context into Raygun!
Added static RaygunClient Attach helper.
Finished all iOS environment values.
Save messages to iOS device when no internet connection.
Finalizing some environment values.
Updated the readme
Ignore Xamarin userprfs files.
Added RaygunClient.Attach helper for iOS
Cleaned up RaygunSettings
Readme updates for iOS