Spotify works again

Fixes #299. This method should be reliable for just about any situation.
However it's only been thoroughly tested by myself. It may break
completely for others. Please provide feedback.

Snip/ApiHelper.cs

@@ -0,0 +1,67 @@
+#region File Information
+/*
+ * Copyright (C) 2006 Michael Schierl
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.
+ */
+#endregion
+
+namespace ManagedWindowsFunctions
+{
+    using System;
+    using System.ComponentModel;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// Helper class that contains static methods useful for API programming. This
+    /// class is not exposed to the user.
+    /// </summary>
+    internal static class ApiHelper
+    {
+        /// <summary>
+        /// Throw a <see cref="Win32Exception"/> if the supplied (return) value is zero.
+        /// This exception uses the last Win32 error code as error message.
+        /// </summary>
+        /// <param name="returnValue">The return value to test.</param>
+        /// <returns>This will return the return value unless it is 0.</returns>
+        /*
+        internal static int FailIfZero(int returnValue)
+        {
+            if (returnValue == 0)
+            {
+                throw new Win32Exception(Marshal.GetLastWin32Error());
+            }
+
+            return returnValue;
+        }
+        */
+
+        /// <summary>
+        /// Throw a <see cref="Win32Exception"/> if the supplied (return) value is zero.
+        /// This exception uses the last Win32 error code as error message.
+        /// </summary>
+        /// <param name="returnValue">The return value to test.</param>
+        /// <returns>This will return the return value unless it is 0.</returns>
+        internal static IntPtr FailIfZero(IntPtr returnValue)
+        {
+            if (returnValue == IntPtr.Zero)
+            {
+                throw new Win32Exception(Marshal.GetLastWin32Error());
+            }
+
+            return returnValue;
+        }
+    }
+}