Adds new database table + migration + unit test + fixes up unit tests to ensure PluginManager.Current = null; is done on teardown.

Created new ServerRegistrationRepository + unit tests + models

src/Umbraco.Core/Configuration/UmbracoVersion.cs

@@ -5,7 +5,7 @@ namespace Umbraco.Core.Configuration
 {
     public class UmbracoVersion
     {
-        private static readonly Version Version = new Version("6.0.0");
+        private static readonly Version Version = new Version("6.1.0");
 
         /// <summary>
         /// Gets the current version of Umbraco.