std: import clone_rename, merge, and Object from lua-stdlib.
std: import clone_rename, merge, and Object from lua-stdlib.

* specl/std.lua (clone_rename, merge, Object): Import from
lua-stdlib.
(M): Export them.

Signed-off-by: Gary V. Vaughan <f9023000f29773649f3850298becb9544b5fd6a9@gnu.org>

gvvaughan/specl