Use seqes as basis for lwtreslib seq
This MR changes the implementation of Seq* in Lwtreslib to use Seqes instead of handrolling it all.
The Seqes library uses functors to replicate the Stdlib Seq module with added monads. Compare to the pre-MR Lwtreslib Seq support it has:
- more thourough tests (including mutation testing)
- complete support for the whole of the Stdlib range of functions
Thus, the present MR:
- removes most of the Seq-related tests
- increases the Seq interface
Incidentally, the monadic traversors are named differently. This is because Seqes being based on functors offers module-based naming. As a result, Seq.iter_e becomes Seq.E.iter (and similarly for other traversors (map, fold_left, etc.) and other suffixes (_s, _es)).
Edited by Raphaël Proust