Concurrent version of PedersenHash isn't working about starkex

[tpunt]

At a quick glance, it looks as though the wg.Add(1) (on line 43) needs to happen outside of the goroutine creation in commit a654684 @yanue

[tpunt]

Actually, I don't see how making the PedersenHash function concurrent like this could work anyway...

Also, the extended Euclidean algorithm implementation (igcdex()) looks broken. E.g. the first if statement is comparing the same conditions.

I've forked the project for now (tpunt/starkex) to apply the fixes, since the owner is not currently around. Happy to create PRs to fix things in this repo when the owner is back (I really don't want to maintain a fork of this).

[emil14]

Awesome! Thank you so much @tpunt