Fixes for running using nuget package

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

src/Umbraco.Configuration/Models/ContentSettings.cs

@@ -73,7 +73,7 @@ namespace Umbraco.Configuration.Models
             _configuration.GetValue(Prefix+"ShowDeprecatedPropertyEditors", false);
 
         public string LoginBackgroundImage =>
-            _configuration.GetValue(Prefix+"LoginBackgroundImage", string.Empty);
+            _configuration.GetValue(Prefix+"LoginBackgroundImage", "assets/img/login.jpg");
 
         private class ContentErrorPage : IContentErrorPage
         {

src/Umbraco.Core/Composing/ReferenceResolver.cs

@@ -62,7 +62,7 @@ namespace Umbraco.Core.Composing
 
                     // don't include this item if it's Umbraco
                     // TODO: We should maybe pass an explicit list of these names in?
-                    if (assemblyName.FullName.StartsWith("Umbraco."))
+                    if (assemblyName.FullName.StartsWith("Umbraco.") || assemblyName.Name.EndsWith(".Views"))
                         continue;
 
                     var assembly = Assembly.Load(assemblyName);

src/Umbraco.Infrastructure/HealthCheck/NotificationMethods/NotificationMethodBase.cs

@@ -19,8 +19,7 @@ namespace Umbraco.Web.HealthCheck.NotificationMethods
             }
 
             var notificationMethods = healthCheckSettingsConfig.NotificationSettings.NotificationMethods;
-            var notificationMethod = notificationMethods[attribute.Alias];
-            if (notificationMethod == null)
+            if(!notificationMethods.TryGetValue(attribute.Alias, out var notificationMethod))
             {
                 Enabled = false;
                 return;