Make RequestParameters work for RT and perf

Around an 80% perf improvement

Octokit/Helpers/ReflectionExtensions.cs

@@ -1,4 +1,8 @@
 using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
 
 namespace Octokit
 {
@@ -11,7 +15,48 @@ namespace Octokit
 
         public static bool IsNullable(this Type type)
         {
-            return type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>);
+            return type.GetTypeInfo().IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>);
+        }
+
+#if !NETFX_CORE
+        public static Type GetTypeInfo(this Type type)
+        {
+            return type;
+        }
+#endif
+
+#if NETFX_CORE
+        public static IEnumerable<MemberInfo> GetMember(this Type type, string name)
+        {
+            return type.GetTypeInfo().DeclaredMembers.Where(m => m.Name == name);
+        }
+
+        public static bool IsAssignableFrom(this Type type, Type otherType)
+        {
+            return type.GetTypeInfo().IsAssignableFrom(otherType.GetTypeInfo());
+        }
+#endif
+        public static IEnumerable<PropertyInfo> GetAllProperties(this Type type)
+        {
+#if NETFX_CORE
+            var typeInfo = type.GetTypeInfo();
+            var properties = typeInfo.DeclaredProperties;
+
+            var baseType = typeInfo.BaseType;
+
+            return baseType == null ? properties : properties.Concat(baseType.GetAllProperties());
+#else
+            return type.GetProperties(BindingFlags.Instance | BindingFlags.Public);
+#endif
+        }
+
+        public static bool IsEnumeration(this Type type)
+        {
+#if NETFX_CORE
+            return type.GetTypeInfo().IsEnum;
+#else
+            return type.IsEnum;
+#endif
         }
     }
 }