Finally stabilize the unit converter.

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1750 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/AttrDef/CSS/Number.php

@@ -18,6 +18,10 @@ class HTMLPurifier_AttrDef_CSS_Number extends HTMLPurifier_AttrDef
         $this->non_negative = $non_negative;
     }
     
+    /**
+     * @warning Some contexts do not pass $config, $context. These
+     *          variables should not be used without checking HTMLPurifier_Length
+     */
     public function validate($number, $config, $context) {
         
         $number = $this->parseCDATA($number);