(Bug 4784) Use default value only if we haven't POSTed yet

Also explain what the default is meant for, to distinguish it from other
ways of setting the visible form field value
(Bug 4414) Convert to TT / routing

Also add a link to refresh this page if we failed to get anything,
rather than redirecting to the front page
(Bug 4414) Try loading a different set of users up to three times
(Bug 4830) Add a link to "Test Beta Features" under "Organize"

Also moves from /betafeatures to /beta.
(Bug 4813) Create a new page /admin/importer/history

* accessible to supporthelps
* lists all the user's imports + current status for each item + time the
  import was scheduled + time the import was last processed
* moved /admin/importer to /admin/importer/queue (including updating the
  link), to prevent confusion since the /history isn't a subset of the
  queue
(Bug 4813) Tie to siteadmin:importhistory priv
(Bug 4707) Explicit base 10, for minimal surprises
(Bug 4773) Use URI module instead of regex

Less work for us to figure out if the ":" in the URL is because of a
port, or it's because of credentials.
(Bug 4773) Strip the credentials from the URL then warn.
(Bug 4699) Allow empty text when deleting an entry
(Bug 4851) Fix operator precedence

What we want:

    ssl && ( GET || HEAD )

What we actually had:

     ( ssl && GET ) || HEAD
Merge pull request #188 from afuna/formdata-checkbox-bug4784

(Bug 4784) Use default value only if we haven't POSTed yet
Merge pull request #224 from afuna/random-journal-bug4414

(Bug 4414) Retry loading random users; show a link if still fail
Merge pull request #225 from afuna/beta-sitemap-bug4830

(Bug 4830) Add a link to "Test Beta Features" under "Organize"
Merge pull request #227 from afuna/support-tool-import-history-bug4813

(Bug 4813) Create a new page /admin/importer/history
Merge pull request #228 from afuna/parseint-bug4707

(Bug 4707) Explicit base 10, for minimal surprises
Merge pull request #230 from afuna/delete-empty-bug4699

(Bug 4699) Allow empty text when deleting an entry
Merge pull request #229 from afuna/feed-credentials-bug4773

(Bug 4773) Make sure users can't create a feed with credentials in the URL
Merge pull request #232 from afuna/head-https-bug4851

(Bug 4851) Fix operator precedence