C++11 features (#778)

* Make noncopyable constructor and destructor default

C++11 provides the functionality.
Defining empty functions cause all classes derived from noncopyable
to be non-trivially constructible and non-trivially destructible.

For example, matrix with compile-time layout by definition does not
require an explicit destructor and should be trivially destructible
; however, deriving from noncopyable makes it non-trivially
destrutible. This also affects vector<T, 2> and vector<T, 3>.

* Delete array2d copy constructor and assignment operators

dlib/array2d/array2d_kernel.h

@@ -160,6 +160,9 @@ namespace dlib
             set_size(rows,cols);
         }
 
+        array2d(const array2d&) = delete;        // copy constructor
+        array2d& operator=(const array2d&) = delete;    // assignment operator
+
 #ifdef DLIB_HAS_RVALUE_REFERENCES
         array2d(array2d&& item) : array2d()
         {
@@ -330,10 +333,6 @@ namespace dlib
         T* last;
         mutable bool at_start_;
 
-        // restricted functions
-        array2d(array2d&);        // copy constructor
-        array2d& operator=(array2d&);    // assignment operator
-
     };
 
 // ----------------------------------------------------------------------------------------

dlib/array2d/array2d_kernel_abstract.h

@@ -122,6 +122,9 @@ namespace dlib
                 - std::bad_alloc 
         !*/
 
+        array2d(const array2d&) = delete;        // copy constructor
+        array2d& operator=(const array2d&) = delete;    // assignment operator
+
         array2d(
             array2d&& item
         );
@@ -252,12 +255,6 @@ namespace dlib
                   An example of such an object is the dlib::cv_image.
         !*/
 
-    private:
-
-        // restricted functions
-        array2d(array2d&);        // copy constructor
-        array2d& operator=(array2d&);    // assignment operator
-
     };
 
     template <

dlib/noncopyable.h

@@ -19,8 +19,8 @@ namespace dlib
         !*/
 
     protected:
-        noncopyable() {}
-        ~noncopyable() {}
+        noncopyable() = default;
+        ~noncopyable() = default;
     private:  // emphasize the following members are private
         noncopyable(const noncopyable&);
         const noncopyable& operator=(const noncopyable&);