support derive

[yyy33]

Add derive macros for some commonly used trails like FromObject

Where set_emap is the function that I expose to the user lua user, wishing to receive the string or table type of the lua

fn set_emap(
    mode: Mode,
    lhs: ,
    rhs: ,
    opts: ,
) -> oxi::Result<()> {
    //TODO
}


#[derive(FromObject)]
enum Mode {
    ByString(String)
    ByTable(Dictionary)
}