Allow pre-commit adapter to use custom actions

Summary: Looks like I missed this when implementing custom actions and hence you can't currently use custom actions on the pre-commit adapters.

Test Plan: Added a custom action to a pre-commit Herald rule.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D10316
Diffusion - nuke faulty javascript error handler

Summary: Fixes T3913.

Test Plan: messed around with a comment on a commit and saw preview still updating correctly

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T3913

Differential Revision: https://secure.phabricator.com/D10382
Diffusion - replace last `hg manifest` call with `hg locate`

Summary: Fixes T4387.

Test Plan: Setup a mercurial repository for rabbitmq-server. Browsed around it and things looked good.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T4387

Differential Revision: https://secure.phabricator.com/D10380
Prevent "Wait for Build Commits" from creating billions of logs

Summary:
Resolves T5987.  This build step was at some point converted to use yielding, which meant that whenever the build step executes it will create a new log.  This checks to see if there is an existing log before creating a new one and uses that instead.

Long term we're going to need some way of attaching data to `PhabricatorWorkerYieldException` that can be read when the build step starts again; this will allow us to move more build steps off `while (...) { ... sleep(X); }` loops and onto yielding.

Test Plan: Tested locally.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley

Maniphest Tasks: T5987

Differential Revision: https://secure.phabricator.com/D10383
Tweak --limit for bin/phd log

Summary:
Ref T5405.

  - `--limit` wasn't actually used anywhere.
  - Make it mean "the N newest lines".

Test Plan: Ran `bin/phd log`, `bin/phd log --limit 3`.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T5405

Differential Revision: https://secure.phabricator.com/D10385
Ponder - fix redirect after leaving a question comment

Summary: we did some security lock down on URI stuff and I think this was a casualty. Fixes T5992.

Test Plan: left a comment, got redirected. no more 500 response.

Reviewers: chad, epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T5992

Differential Revision: https://secure.phabricator.com/D10388
Flag - fix purple flag

Summary: purple != violet, and in our CSS we call these things by the fanciest of terms. Fixes T5995.

Test Plan: flagged something purple and saw that the "remove purple flag" flag was indeed purple. quickly tested other colors and they all seem good too.

Reviewers: epriestley, chad

Reviewed By: chad

Subscribers: epriestley, Korvin

Maniphest Tasks: T5995

Differential Revision: https://secure.phabricator.com/D10389
phutil_utf8_shorten => PhutilUTF8StringTruncator

Summary: Ref T3307. Only one I thought was tricky was Excel; I went with bytes there like it was email.

Test Plan: played around on a few endpoints but mostly thought carefully

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T3307

Differential Revision: https://secure.phabricator.com/D10392