Migrated from using WebClient to WebRequest
Merge branch 'master' into async-csharp-five

Conflicts:
	app/Pomona.Common/Web/IWebClient.cs
	app/Pomona.Common/Web/WrappedWebClient.cs
	tests/Pomona.SystemTests/ClientTestsBase.cs
	tests/Pomona.TestHelpers/NancyTestingWebClient.cs
Fixed files after merge
Implemented support for If-Match and etag stuff.
Merge branch 'master' into async-csharp-five

Conflicts:
	app/Pomona.Common/ClientBase.cs
	app/Pomona.Common/Pomona.Common.csproj
	tests/Pomona.SystemTests/ClientTestsBase.cs
Fixed compile-error after merge from master