Fixed GetClassTypeReference resolving error.

Use case: Lib uses System.Core 3.5, Project 4.0 - the 3.5 assembly
can't be resolved in the project context.

ICSharpCode.NRefactory/TypeSystem/Implementation/GetClassTypeReference.cs

@@ -73,25 +73,35 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 		public string Name { get { return name; } }
 		public int TypeParameterCount { get { return typeParameterCount; } }
 		
-		public IType Resolve(ITypeResolveContext context)
+		IType ResolveInContext(ITypeResolveContext context)
 		{
-			if (context == null)
-				throw new ArgumentNullException("context");
-			
 			IType type = null;
-			if (assembly == null) {
 			var compilation = context.Compilation;
-				foreach (var asm in new[] { context.CurrentAssembly }.Concat(compilation.Assemblies)) {
+			foreach (var asm in new[] {
+				context.CurrentAssembly
+			}.Concat (compilation.Assemblies)) {
 				if (asm != null) {
 					type = asm.GetTypeDefinition(nameSpace, name, typeParameterCount);
 					if (type != null)
 						return type;
 				}
 			}
+			return type;
+		}
+
+		public IType Resolve(ITypeResolveContext context)
+		{
+			if (context == null)
+				throw new ArgumentNullException("context");
+			IType type = null;
+			if (assembly == null) {
+				type = ResolveInContext(context);
 			} else {
 				IAssembly asm = assembly.Resolve(context);
 				if (asm != null) {
 					type = asm.GetTypeDefinition(nameSpace, name, typeParameterCount);
+				} else {
+					type = ResolveInContext(context);
 				}
 			}
 			return type ?? new UnknownType(nameSpace, name, typeParameterCount);