Escape story fields and clean story HTML with HTML Purifier.

Add HTML Purifier 4.19.1. Stories are purified when they are saved and
when they are shown.

lib/htmlpurifier-4.19.1/library/HTMLPurifier/ConfigSchema/schema/HTML.Parent.txt

@@ -0,0 +1,12 @@
+HTML.Parent
+TYPE: string
+VERSION: 1.3.0
+DEFAULT: 'div'
+--DESCRIPTION--
+
+<p>
+    String name of element that HTML fragment passed to library will be
+    inserted in.  An interesting variation would be using span as the
+    parent element, meaning that only inline tags would be allowed.
+</p>
+--# vim: et sw=4 sts=4