Basic autocomplete for admin posts tags

Similar to the skins autocomplete: basic LIKE search, maximum MAX_RECENT items. Can be tweaked by further requests.
Rake task to destroy all unused admin post tags
3806 add Twitter Javascript to chapters/show
3806 Move Twitter JavaScript to work navigation partial so it is included for chapters
3812 Admin post filter labels should select associated form elements
3812 Make Filters text on admin posts index translateable
get the types required for matching in a particular challenge
Major revision of potential matching for speed

This drastically reduces the time it takes to generate potential matches for a large challenge with many options by reducing the number of signups checked to only those that have any chance of a match (i.e., sharing at least one required tag). Finding these signups can be done with fast SQL-only queries.

Signed-off-by: Naomi Novik <shalott@gmail.com>
Fixing progress percentage report

Signed-off-by: shalott <shalott@gmail.com>
Per-signup regeneration, refactoring potential match listing

Allow regenerating potential matches for individual signups.

Also refactor the listing for more clarity and readability, and also preventing no-potential-match participants from blocking the view of the rest of the collection.

Signed-off-by: shalott <shalott@gmail.com>
Move per-signup regeneration into the background

Signed-off-by: shalott <shalott@gmail.com>
Increased layout consistency on the potential matches index page

Signed-off-by: shalott <shalott@gmail.com>
minor fixes

Signed-off-by: shalott <shalott@gmail.com>
Tweaks and tests for potential matching upgrade

Signed-off-by: shalott <shalott@gmail.com>
cleanup

Signed-off-by: shalott <shalott@gmail.com>
restoring the clear of the potential matches if canceled

Signed-off-by: shalott <shalott@gmail.com>
Moving wordy confusing explanations into help file

This hopefully provides better context and clearer explanations for how to deal with matching issues, and gets too-wordy and confusing text out of the matching page.

Signed-off-by: shalott <shalott@gmail.com>
Cleanup of tests and bringing tests and new code back in line

Signed-off-by: shalott <shalott@gmail.com>
Corrected user-facing spelling of sign-up and some more test improvements

Signed-off-by: Naomi Novik <shalott@gmail.com>
test fix

Signed-off-by: Naomi Novik <shalott@gmail.com>