make Array::grow/resize from baseclass private

We don't really want the user to use the 1D grow/resize functions, but
in the previous commit they were exposed. So, make them private.

Author: KrisThielemans

src/include/stir/Array.h

@@ -203,9 +203,6 @@ class Array : public NumericVectorWithOffset<Array<num_dimensions - 1, elemT>, e
   //! return the total number of elements in this array
   inline size_t size_all() const;
 
-  using base_type::grow;
-  using base_type::resize;
-
   //! change the array to a new range of indices, new elements are set to 0
   /*! Current behaviour is that when resizing to a smaller array, the same memory
     will be used. However, when growing any of the dimensions, a new Array
@@ -331,6 +328,9 @@ class Array : public NumericVectorWithOffset<Array<num_dimensions - 1, elemT>, e
   // Make sure that we can access init() recursively
   template <int num_dimensions2, class elemT2>
   friend class Array;
+
+  using base_type::grow;
+  using base_type::resize;
 };
 
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