Translation update (fr)

Translation update (zh)

Translation update (de)

Translation update (de)

Translation update (pt-br)

Translation update (cs)

* Added missing 'userchangefail' in English to authad.

Fix typo in Spanish ACL help.txt

Updated a word wrongly written on spanish

Translation update (es)

Translation update (ja)

Add an in-progress class to the quicksearch form.

Translation update (ru)

Show specific error messages if user creation fails

fix typo in German translation

This change adds a new class to the quicksearch's <form>
element while the quicksearch is running. This is to
make it easier to style the form, e.g. with a throbber gif
in the search box, to indicate that something is happening.
For slow connections, it is sometimes not apparent that
waiting for a few seconds will present the user with a list
of matching pagenames.

The new 'searching' class is added just before the POST
request is sent, and cleared both on successful completion
and when the search box is cleared.

Fix for PHP 7, more debugging output

Optimizations to autoloader

Autoloader should return true if it can handle the class so other registered autoloader don't execute.
require is faster than require_once and should be safe to use since the autoloader won't run if the class already exists

add convenience function for empty check without 0

This allows to quickly check if a variable is empty but keeps strings
and numbers evaluating to zero.