C++11-ify NonCopyable

Define copy operators public and deleted rather declaring them private
and undefined. Will give immediate compilation errors rather than
delayed linking errors.

Author: kjbracey

platform/NonCopyable.h

@@ -211,18 +211,17 @@ class NonCopyable {
     }
 
 #else
-private:
     /**
      * Declare copy constructor as private. Any attempt to copy construct
      * a NonCopyable will fail at compile time.
      */
-    NonCopyable(const NonCopyable &);
+    NonCopyable(const NonCopyable &) = delete;
 
     /**
      * Declare copy assignment operator as private. Any attempt to copy assign
      * a NonCopyable will fail at compile time.
      */
-    NonCopyable &operator=(const NonCopyable &);
+    NonCopyable &operator=(const NonCopyable &) = delete;
 #endif
 #endif
 };