NSError init issue

[randallrvr]

NSError init issue

[tony-davis]

The "empty" initializer for ns::Error doesn't exist anymore (it never really made sense anyway), and I believe the correct way to handle this is to have a "nil" object instead.

Here's how I addressed the error, starting in mtlpp.mm, line 2422:

   Error::Error() :
       Object(Handle{ nil })
   {

   }

Let me know if anyone agrees with this fix.