This adds a new parameter to ft_backlinks() to ignore permissions which
is needed for invalidating the cache of linking pages with useheading
enabled. This also adds various test cases for ft_backlinks().

the _redirect function is not used in DokuWiki anyway

If you want better random initialization and more control over the
password strength install the passpolicy plugin.

This is needed to replace the password generator by a plugin
implementation. Related to PR #166 and FS#2147

No need for HMAC here because there's no length attack vector here. We
only care for the existance of the file and each reset request is
completely (random) independent from each other.

ml() can built url to these images, either fetch didn't accept them.

The resize token was broken because fetch.php cleans the id before the token calculation, while ml() uses the raw id

Clarify use of _escape() method in base class.

ensure security token is included in media url when resize parameter is passed in string form, e.g. 'w=80'

The code that is removed in this commit has either never been used
(listIndexLenghts) or was completely broken (cacheIndexDir) and was
introduced in the indexer rewrite in 2010. The idea of the rewrite was
to update the readdir cache after every index change instead of on demand.
What the code actually did was removing every updated index from the
cache as it used a wrong if condition. Simply fixing the condition
wouldn't fix the problem as then only updated indexes would be added to
the cache and furthermore the rewrite simply ignored the readdircache
setting. For now the safest solution seems to be removing the code. It
could be added again in a changed form in a future version.