Moderate a post or topic

Adds actions to moderate topics and attempts to fixes issues with application of
delete and censor.  Also adjusts action menu to deny actions if its a state
transition to the existing state.

To be done in a future patch
* When 10 items are requested by infinite scroll, but 2 are
  not visible to the user, only sends back the 8 visible topics

Change-Id: I10cae63c2491c9f467968d6f8d604ea7f743ea96