Implements Nullable support

Author: AlexCatarino

src/runtime/converter.cs

@@ -507,6 +507,12 @@ internal static bool ToManagedValue(IntPtr value, Type obType,
                 return false;
             }
 
+            var underlyingType = Nullable.GetUnderlyingType(obType);
+            if (underlyingType != null)
+            {
+                return ToManagedValue(value, underlyingType, out result, setError);
+            }
+
             return ToPrimitive(value, obType, out result, setError);
         }
 
@@ -966,7 +972,7 @@ private static bool ToArray(IntPtr value, Type obType, out object result, bool s
             int size = Runtime.PySequence_Size(value);
             result = null;
 
-            if (size < 0)
+            if (size < 0 || elementType.IsGenericType)
             {
                 if (setError)
                 {

src/runtime/methodbinder.cs

@@ -394,8 +394,14 @@ internal Binding Bind(IntPtr inst, IntPtr args, IntPtr kw, MethodBase info, Meth
                                     }
                                     if (!typematch)
                                     {
+                                        // this takes care of nullables
+                                        var underlyingType = Nullable.GetUnderlyingType(pi[n].ParameterType);
+                                        if (underlyingType == null)
+                                        {
+                                            underlyingType = pi[n].ParameterType;
+                                        }
                                         // this takes care of enum values
-                                        TypeCode argtypecode = Type.GetTypeCode(pi[n].ParameterType);
+                                        TypeCode argtypecode = Type.GetTypeCode(underlyingType);
                                         TypeCode paramtypecode = Type.GetTypeCode(clrtype);
                                         if (argtypecode == paramtypecode)
                                         {