Merge branch 'dev-v7' into temp8

# Conflicts:
#	docs/CONTRIBUTING_DETAILED.md
#	docs/README.md
#	src/Umbraco.Core/Configuration/GlobalSettings.cs
#	src/Umbraco.Core/StringExtensions.cs
#	src/Umbraco.Web.UI.Client/src/common/directives/components/buttons/umbbutton.directive.js
#	src/Umbraco.Web.UI.Client/src/less/components/umb-group-builder.less
#	src/Umbraco.Web.UI.Client/src/views/components/buttons/umb-button.html
#	src/Umbraco.Web.UI.Client/src/views/dashboard/developer/developerdashboardvideos.html
#	src/Umbraco.Web.UI.Client/src/views/prevalueeditors/boolean.controller.js
#	src/Umbraco.Web.UI.Client/src/views/propertyeditors/boolean/boolean.html
#	src/Umbraco.Web/PublishedContentExtensions.cs
#	src/Umbraco.Web/Trees/LanguageTreeController.cs

src/Umbraco.Tests/Strings/StringExtensionsTests.cs

@@ -165,6 +165,29 @@ namespace Umbraco.Tests.Strings
             Assert.AreEqual(expected, output);
         }
 
+        [TestCase("", true)]
+        [TestCase(" ", true)]
+        [TestCase("\r\n\r\n", true)]
+        [TestCase("\r\n", true)]
+        [TestCase(@"
+        Hello
+        ", false)]
+        [TestCase(null, true)]
+        [TestCase("a", false)]
+        [TestCase("abc", false)]
+        [TestCase("abc   ", false)]
+        [TestCase("   abc", false)]
+        [TestCase("   abc   ", false)]
+        public void IsNullOrWhiteSpace(string value, bool expected)
+        {
+            // Act
+            bool result = value.IsNullOrWhiteSpace();
+
+            // Assert
+            Assert.AreEqual(expected, result);
+        }
+
+
         // FORMAT STRINGS
 
         // note: here we just ensure that the proper helper gets called properly