Add Copy Constructor to CProxyElement_ArrayBase (#3437)

* Add Copy Constructor to CProxyElement_ArrayBase

* Add Copy-Assign to Satisfy 'Rule of Two'

Author: jszaday

src/ck-core/ckarray.h

@@ -169,8 +169,17 @@ class CProxyElement_ArrayBase : public CProxy_ArrayBase
       : CProxy_ArrayBase(aid), _idx(idx)
   {
   }
+  CProxyElement_ArrayBase(const CProxyElement_ArrayBase& other)
+      : CProxy_ArrayBase(other.ckGetArrayID()), _idx(other.ckGetIndex())
+  {
+  }
   CProxyElement_ArrayBase(const ArrayElement* e);
 
+  CProxyElement_ArrayBase& operator=(const CProxyElement_ArrayBase& other)
+  {
+    return *this = CProxyElement_ArrayBase(other);
+  }
+
   bool operator==(const CProxyElement_ArrayBase& other)
   {
     return ckGetArrayID() == other.ckGetArrayID() && ckGetIndex() == other.ckGetIndex();