many PHPDocs
some unused variables
some dynamically declared variables declared

When a username but no password is submitted, the login is denied right
away instead of relying on the backend to refuse the login.

This is to prevent zero byte attacks on external auth systems as
described in
http://www.freelists.org/post/dokuwiki/Fwd-Dokuwiki-maybe-security-issue-Null-byte-poisoning-in-LDAP-authentication

the filter() function can be chained between the accessor and the value
function to get a filtered value. When no filter allable is given in the
filter() function, stripctl() is used to strip all control chars (ASCII<32)

Examples:

  $INPUT->post->filter()->str('foobar');
  $INPUT->get->filter('myfilter')->int('baz');

autorisations suffisants -> permissions suffisantes

This should avoid problems when a WiFi login redirect intercepts the
update check.
See https://forum.dokuwiki.org/post/45076

* support namespaces with more then one level e.g. @your:namespace
* support ns:<ns> as well

as discussed in 22db8df7