R1:946a5cd5ceb7

Allow ponder answers to be edited

Summary:
Ref T3373. Use applicationtransactions to edit ponder answers.

Also enable tokens and subscriptions.

Test Plan: edited an answer

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T3373

Differential Revision: https://secure.phabricator.com/D6607