Expression: Drop dedup from scalars and scalars_mut (#56)
Expression: Drop dedup from scalars and scalars_mut (#56)

As the function documentation states, *all* scalars used in the
expression will be returned. Therefore, the dedup is not correct
as the caller expects all scalar instances. This is especially
true when mutating the scalars, as otherwise some scalars which
appear multiple times with same name will be missed.

E.g. x + y * x should give [x, y, x] instead of [x, y]
     -> misses second x instance with dedup!

If the caller only requires the names of the scalars appearing in
the expression, then the caller could simply call dedup.
falconre/falcon,endeav0r/falcon,endeav0r/falcon,endeav0r/falcon,falconre/falcon,falconre/falcon,endeav0r/falcon