Changeset 3898

Support Forums: Add some helper classes prior to inclusion.

Hooks provides some minor visual changes for common bbPress display filters.

Dropin replaces functions that walk ancestors with those that do not. In forums where there are several hundred thousand topics and millions of replies, these operations become prohibitively expensive.

This is intended to mitigate a white-screen-of-death problem experienced on front-end actions such as new topic, trash topic, etc. after we crossed the two million topic threshold.