fix(library/io_state): bug in the io_state Lua bindings

This commit also includes a new test that exposes the problem.
The options in the io_state object were being lost.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(frontends/lean): macro definition using Lua

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(frontends/lean): macro definition using Lua