Allow reviewing disputed claims made by people in your invite chain

[danfinlay]

Story:

1. Alice invites Bob
2. Bob invites Carol
3. Carol reports Edmund
4. Someone else in the system un-reports Edmund
5. Alice and Bob each can now see one of their invitations led to the disputed report of Edmund.
6. They are able to review the disputed claim, and choose to revoke their invitation if they like (to Bob or Carol, respectively).

Bob has an incentive to be quick to review his disputes, because if he doesn't, Alice might revoke his membership!