Add jQuery.textcomplete
Add support for auto-completing placeables
Improve placeables inside right-to-left text

Make them embedded left-to-right strings so that things like “%(foo)s”
do not look like “foo)s)%” inside right-to-left strings (which can be
seen when setting, say, Arabic as an alt source language).

This does not affect translation field (which would benefit from this
most), though.
Fix the placement of the auto complete drop down

For some reason we need to force block here otherwise the placement is
off in Firefox.
Escape HTML in autocomplete dropdown
Bugfix: There is no flush_checks
Cleanup: Move code to upgrade management command

Since it is the only place where it is used it makes sense to be there.
This allows to keep the module __init__.py for code more focused on the
upgrade machinery internals.
Cleanups

To ease further refactoring and improve readability.
Cleanup: Provided build versions are always integers

So avoid the conversion.
Cleanup: Now `buildversion_for_fn` always returns an int

So no need to convert the retrieved build version in other places.
Cleanup: Pass the function instead of the function name
Cleanup: `filter_upgrade_functions` already receives the function build

Still wondering why this code worked.
Cleanup: Just do the comparison instead of calling function
Cleanup: Remove intermediate upgrade function
Bugfix: Use the right build versions