Updates BackgroundTaskRunner to ensure canceled or skipped tasks are disposed, updated tests to reflect

src/Umbraco.Web/Scheduling/BackgroundTaskRunnerOptions.cs

@@ -0,0 +1,23 @@
+namespace Umbraco.Web.Scheduling
+{
+    internal class BackgroundTaskRunnerOptions
+    {
+        //TODO: Could add options for using a stack vs queue if required
+
+        public BackgroundTaskRunnerOptions()
+        {
+            DedicatedThread = false;
+            PersistentThread = false;
+            OnlyProcessLastItem = false;
+        }
+
+        public bool DedicatedThread { get; set; }
+        public bool PersistentThread { get; set; }
+
+        /// <summary>
+        /// If this is true, the task runner will skip over all items and only process the last/final 
+        /// item registered
+        /// </summary>
+        public bool OnlyProcessLastItem { get; set; }
+    }
+}