Macro impl_ops

macro_rules! impl_ops {
    (
        $type: ty,
        $native: ty,
        $trait: ident,
        $fn: ident,
        $assign_trait: ident,
        $assign_fn: ident,
        $impl: expr,
        $constant_impl: expr,
        $($args:tt)*
    ) => { ... };
}

Implements arithmetic traits (eg: Add, Sub, Mul) for the given type using the impl in $impl.

Used primarily for implementing these traits for FieldVars and GroupVars.