kses whitelisted URL protocols
==============================

From kses 0.2.0, it has a function that checks all attribute values for URL
protocols and only allows the protocols given in a whitelist.

If you call kses the old way with two parameters - a string and an
$allowed_html array - it will take its own default array, which whitelists the
protocols http, https, ftp, news, nntp, telnet, gopher and mailto. Pretty
reasonable, but anyone who wants to change it just calls the kses() function
with a third parameter, like this:

$string = kses($string, $allowed_html, array('http', 'https'));

Note that you shouldn't include any colon after http or other protocol names.