Clean topic/reply post cache on certain actions

[thebrandonallen]

When working with counts, our caching layer causes some counts to be out of sync. Included patch remedies this situation.

This patch goes along with the improved count tests I'm adding to another ticket. I'll link to it when I've created it.

[johnjamesjacoby]

Fixed in r5733. See #2801.

[thebrandonallen]

Attached patch does two things:

1) Condenses the majority of our bbp_clean_post_cache actions onto WP's clean_post_cache hook.

2) Reworks bbp_clean_post_cache() to function better with the post type agnostic clean_post_cache hook.

The result is that our current tests pass without having to manually call bbp_clean_post_cache(), and all of our factory create methods now have cache clearing built in. All of our existing tests continue to pass.

As our test base builds up, we should probably audit the other areas where we're calling bbp_clean_post_cache, either directly or via hook. We may be able to remove some of them.

[thebrandonallen]

Cache cleaning improvements

[johnjamesjacoby]

This seems much more sane. Nice work.

[johnjamesjacoby]

In 5774:

Cache: Much more sane cache invalidation.

This change improves hierarchical forum/topic/reply cache invalidations by not requiring each call to be strategically placed between actions to avoid race conditions.

Props thebrandonallen. Fixes #2800.