did not compile on mac, don't know why to prohibit copying; refs #7

src/mrw/configfile.hxx

@@ -227,7 +227,7 @@ namespace mrw {
             value = newValue;
             return *this;
           }
-      
+
           /// Compare the value to a string.
           bool operator==(const std::string& o) const throw() {
             return o==value;
@@ -264,7 +264,6 @@ namespace mrw {
         private:
       
           Value(); // not implemented, must be initialized
-          Value& operator=(const Value&); // not implemented, no assignment
       
       };
       //------------------------------------------------------------------------