5.x

#494276: Only superuser can bulk export

Contains fixes for..
#449220: Blog homepage context
#492258: page_title_install() out of date

Fixed #494212: Registration form toggles on and off on refresh.

Fixed bug where Role Limits wasn't honoring 0 and turning registrations back on.
Refactored registration code into it's own function. See role_limits_registration($on) for details.

A complete rewrite by danielnolde:

- db-storage with multiple fields, with (per code):
* role granting by code
* expiry of availability
* one-time-only or re-usable codes
* tracking of code-usage (user, date)
* info-column for freestyle-usage
- filter- and order-able code listing / search
- import (with flexible CSV--setting, file-upload- or textarea-import and a default code-data-template)
- permission to override even mandatory regcode-input for adding new users (helpful for admins)

Added exclude blocked users to authenticated settings.
Added registration disabled when the authenticated limit has been reached.
Added language to user admin settings form to alert user when Role Limits has set the options.