Add an application-specific exception.

Author: walterpinson

src/Core/Application/Exceptions/NoteTakerException.cs

@@ -0,0 +1,10 @@
+namespace CompanyName.Notebook.NoteTaking.Core.Application.Exceptions
+{
+    using System;
+
+    public class NoteTakerException : Exception
+    {
+        public NoteTakerException(string message, Exception innerException=null)
+            :base(message, innerException) { }
+    }
+}