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/AutoFormat.AutoParagraph.txt

@@ -0,0 +1,31 @@
+AutoFormat.AutoParagraph
+TYPE: bool
+VERSION: 2.0.1
+DEFAULT: false
+--DESCRIPTION--
+
+<p>
+  This directive turns on auto-paragraphing, where double newlines are
+  converted in to paragraphs whenever possible. Auto-paragraphing:
+</p>
+<ul>
+  <li>Always applies to inline elements or text in the root node,</li>
+  <li>Applies to inline elements or text with double newlines in nodes
+      that allow paragraph tags,</li>
+  <li>Applies to double newlines in paragraph tags</li>
+</ul>
+<p>
+  <code>p</code> tags must be allowed for this directive to take effect.
+  We do not use <code>br</code> tags for paragraphing, as that is
+  semantically incorrect.
+</p>
+<p>
+  To prevent auto-paragraphing as a content-producer, refrain from using
+  double-newlines except to specify a new paragraph or in contexts where
+  it has special meaning (whitespace usually has no meaning except in
+  tags like <code>pre</code>, so this should not be difficult.) To prevent
+  the paragraphing of inline text adjacent to block elements, wrap them
+  in <code>div</code> tags (the behavior is slightly different outside of
+  the root node.)
+</p>
+--# vim: et sw=4 sts=4