Use default copy operator

Author: flanglet

src/Context.hpp

@@ -54,7 +54,7 @@ namespace kanzi
        Context(ThreadPool* p = nullptr) : _pool(p) {}
        Context(const Context& c) : _map(c._map), _pool(c._pool) {}
        Context(const Context& c, ThreadPool* p) : _map(c._map), _pool(p) {}
-       Context& operator=(const Context& c) { _map = c._map; _pool = c._pool; return *this; };
+       Context& operator=(const Context& c) = default;
 #else
        Context() {}
        Context(const Context& c) : _map(c._map) {}