Fix every HTML issue I could find

Summary:
I attempted to test every interface. I probably missed some stuff, but I at least have some level of confidence that the `phutil_tag` branch is fairly stable.

Fixed these issues:

[1] Fixed a Herald issue with object links in transcripts. Some actions return
links; this was previously hard-coded.
[2] DarkConsole refactoring created an issue where the "`" event handler registered too many times.
[3] Fixed a bug where `strlen($value)` was being checked, but fields may now return array(). Possibly we should implement phutil_is_empty_html() or similar.
[4] Fixed a undefined variable issue for image edit transactions.
[5] Fixed an issue with rendering participant transactions. This required phutil_safe_html() because `pht()` can't handle `array()` for `%s`.
[6] Fixed an issue where feed was entirely overescaped by reverting an overly ambitious render_tag -> tag.
[7] Fixed an issue with strict tables and inserting `''` instead of `0` into an integer column.
[8] Fixed an issue where &bull; was shown escaped.
[9] Fixed an issue where "no data" was overescaped.
[10] Fixed an issue with strict tables and inserting `''` instead of `0` into an integer column.
[11] Fixed an issue with strict tables and inserting `''`.
[12] Fixed an issue with missing space after ":" for mini panels.

Encountered (but did not fix) these issues:

[X1] "e" works incorrectly on comments you are not allowed to edit. Did not fix.
[X2] Coverage currently interacts incorrectly with "--everything" for Phutil tests.

Test Plan:
  - Viewed Differential.
  - Created a diff via copy/paste.
  - Viewed standalone diff.
  - Jumped to diff via changeset table.
  - Created a revision.
  - Updated revision.
  - Added a comment.
  - Edited revision dependencies.
  - Edited revision tasks.
  - Viewed MetaMTA transcripts.
  - Viewed Herald transcripts [1].
  - Downloaded raw diff.
  - Flagged / unflagged revision.
  - Added/edited/deleted inline comment.
  - Collapsed/expanded file.
  - Did show raw left.
  - Did show raw right.
  - Checked previews for available actions.
  - Clicked remarkup buttons
  - Used filetree view.
  - Used keyboard: F, j, k, J, K, n, p, t, h, "?" [2] [X1].
  - Created a meme.
  - Uploaded a file via drag and drop.
  - Viewed a revision with no reviewers.
  - Viewed a revision with >100 files.
  - Viewed various other revisions [3].
  - Viewed an image diff.
  - Added image diff inline comments.
  - Viewed Maniphest.
  - Ran various queries.
  - Created task.
  - Created similar task.
  - Added comments to tasks.
  - Ran custom query.
  - Saved custom query.
  - Edited custom queries.
  - Drag-reordered tasks.
  - Batch edited tasks.
  - Exported tasks to excel.
  - Looked at reports (issue in T2311 notwithstanding).
  - Viewed Diffusion.
  - Browsed Git, SVN, HG repositories.
  - Looked at history, browse, change, commit views.
  - Viewed audit.
  - Performed various audit searches.
  - Viewed Paste.
  - Performed paste searches.
  - Created, edited, forked paste.
  - Viewed Phriction.
  - Edited a page.
  - Viewed edit history.
  - Used search typeahead to search for user / application.
  - Used search to search for text.
  - Viewed Phame.
  - Viewed Blog, Post.
  - Viewed live post.
  - Published/unpublished post.
  - Previewed post.
  - Viewed Pholio.
  - Edited/commented mock.
  - Viewed ponder.
  - Viewed question.
  - Added answer/comment.
  - Viewed Diviner.
  - Viewed Conpherence [4] [5].
  - Made Conpherence updates.
  - Viewed calendar.
  - Created status.
  - Viewed status.
  - Viewed Feed [6].
  - Viewed Projects.
  - Viewed project detail.
  - Edited project.
  - Viewed Owners.
  - Viewed package detail.
  - Edited package [7].
  - Viewed flags.
  - Edited flag.
  - Deleted flag.
  - Viewed Herald.
  - Viewed rules.
  - Created rule.
  - Edited rule.
  - Viewed edit log.
  - Viewed transcripts.
  - Inspected a transcript.
  - Viewed People.
  - Viewed list.
  - Administrated user.
  - Checked username/delete stuff.
  - Looked at create/import LDAP/activity logs.
  - Looked at a user profile.
  - Looked at user about page.
  - Looked at Repositories.
  - Edited repository.
  - Edited arcanist project.
  - Looked at daemons.
  - Looked at all daemons [8].
  - Viewed combined log.
  - Looked at configuration.
  - Edited configuration.
  - Looked at setup issues [9].
  - Looked at current settings.
  - Looked at application list.
  - Installed / uninstalled applications [10].
  - Looked at mailing lists.
  - Created a mailing list.
  - Edited a mailing list.
  - Looked at sent mail.
  - Looked at received mail.
  - Looked at send/receive tests.
  - Looked at settings.
  - Clicked through all the panels.
  - Looked at slowvote.
  - Created a slowvote [11].
  - Voted in a slowvote.
  - Looked at Macro.
  - Created a macro.
  - Edited a macro.
  - Commented on a macro.
  - Looked at Countdown.
  - Created a Countdown.
  - Looked at it.
  - Looked at Drydock.
  - Poked around a bit.
  - Looked at Fact.
  - Poked around a bit.
  - Looked at files.
  - Looked at a file.
  - Uploaded a file.
  - Looked at Conduit.
  - Made a Conduit call.
  - Looked at UIExamples.
  - Looked at PHPAST.
  - Looked at PHIDs.
  - Looked at notification menu.
  - Looked at notification detail.
  - Logged out.
  - Logged in.
  - Looked at homepage [12].
  - Ran `arc unit --everything --no-coverage` [X2].

Reviewers: vrana, btrahan

Reviewed By: vrana

CC: aran

Maniphest Tasks: T2432

Differential Revision: https://secure.phabricator.com/D4807