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.TargetBlank.txt

@@ -0,0 +1,8 @@
+HTML.TargetBlank
+TYPE: bool
+VERSION: 4.4.0
+DEFAULT: FALSE
+--DESCRIPTION--
+If enabled, <code>target=blank</code> attributes are added to all outgoing links.
+(This includes links from an HTTPS version of a page to an HTTP version.)
+--# vim: et sw=4 sts=4