RavenDB-1134 PatchOrPut semantics using only PATCH
Merge branch 'RavenDB-1134' of https://github.com/jahmai/ravendb into RavenDB-1134

Conflicts:
	Raven.Client.Embedded/EmbeddedAsyncServerClient.cs
	Raven.Client.Embedded/EmbeddedDatabaseCommands.cs
	Raven.Client.Lightweight/Connection/Async/AsyncDatabaseCommandsExtensions.cs
	Raven.Client.Lightweight/Connection/Async/AsyncServerClient.cs
	Raven.Client.Lightweight/Connection/Async/IAsyncDatabaseCommands.cs
	Raven.Client.Lightweight/Connection/IDatabaseCommands.cs
	Raven.Client.Lightweight/Connection/ServerClient.cs
	Raven.Database/Extensions/CommandExtensions.cs
	Raven.Tests/Document/DocumentStoreServerTests.cs