add support for XML-Doc located in 4.5 and 4.5.1 .NET frameworks

src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/XmlDoc.cs

@@ -15,6 +15,8 @@ namespace ICSharpCode.SharpDevelop.Dom
 	public sealed class XmlDoc : IDisposable
 	{
 		static readonly List<string> xmlDocLookupDirectories = new List<string> {
+			Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86), @"Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5.1"),
+			Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86), @"Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5"),
 			Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86), @"Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0"),
 			System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory()
 		};