Remove m2helpers module in contrib

There are other modules that can now validate HTTPS
connections, so this is no longer necessary.
Remove m2crypto as a dependency
Merge branch 'no-m2crypto' into develop

As mentioned in #1214, the old contrib code m2helpers
is no longer needed so it's being removed, and as a result
we longer depend on m2crypto.

* no-m2crypto:
  Remove m2crypto as a dependency
  Remove m2helpers module in contrib