Revert "Fix adding tags"

This reverts commit aa04852e9b9c6a88f4c68c5b9d7502fde1b7b8cc.

Next commit will fix it in a less hacky way.
Unbreak AJAX views using @get_path_obj

Since a81fa7b8f477eb9ab4b2bd8b9cacfdcc8630b566 @get_path_obj requires
that the request provide a ‘path’, but most of our AJAX requests do not
provide one, which breaks views that use @get_path_obj, so relax this
requirement and use the ‘path’ only when provided.
langpicker: Various UI fixes

See bug #3181
js: Update select2 to 3.4.5

One of the things we need most of all is diacritics support, for the
language picker.

See: https://github.com/ivaynberg/select2/issues/1472
breadcrumbs: Remove the style="visibility: hidden" from select2 menus

The select2 update takes care of doing this for us; if we leave it in
the initial style the select2 menu will copy it and the menu disappears.
js: Update the languages.js file to match LINGUAS
coverage: enable test coverage
Unbreak update_against_templates with goals

It was broken since b3edd98 as post_template_update and post_vc_update
signals no longer have ‘oldstats’ or ‘newstats’ args, so check for their
presence first.
Add missing import

pootle_store/decorators.py was missing Store import and thus caused
tracback with: NameError: global name 'Store' is not defined trying to
download a file.
Use the new parent icon in goals tab
Docs: Advertise that LDAP auth backend moved in 2.5.1 release notes
Simplify and fix path summary more

AKA Expand Details link, which was broken since 4980547.
Drop the extra AJAX request for path summary
Move the bulk of path summary code to JS

This avoids the extra database queries to calculate completion
percentages.
Cosmetic
allauth: Enable OpenID and Persona login support by default
allauth: Redesign the social account registration page
allauth: Document new features in the release notes

Also move it up in the roadmap.
allauth: docs: Document allauth/social auth support
allauth: Drop a redundant dir attribute