1.x-1.0.1

Three Drupal 7 assumptions that Backdrop does not satisfy, all of which failed silently rather than raising an error.

Fixed membership roles never being revoked on expiry, and role assignment raising a duplicate key error on {users_roles} at every renewal.
$account->roles is an unindexed array in Backdrop, not keyed by role ID as in Drupal 7.

Fixed a user's memberships being silently collapsed to one per type, which lost data on user deletion by orphaning the discarded membership.

Fixed #4 Join links resolving to membership type management rather than the join form. Backdrop's core Entity class has no entityInfo property, so the guard in MembershipEntityType::uri() was never true and every context fell through to the admin path.