Add website to client repository

Closes #1567

The main reason I'm not simply merging Annika's PR is because this
way makes it clearer that I'm taking responsibility for all this
code, that it's mostly code I wrote, and also because it makes it
easier to ensure that none of the files have been changed.

(Not that I don't personally trust Annika, but I have something
resembling an obligation to users not to expose them to risks based
on personal trust.)

website/lib/htmlpurifier/HTMLPurifier/ConfigSchema/schema/HTML.BlockWrapper.txt

@@ -0,0 +1,18 @@
+HTML.BlockWrapper
+TYPE: string
+VERSION: 1.3.0
+DEFAULT: 'p'
+--DESCRIPTION--
+
+<p>
+    String name of element to wrap inline elements that are inside a block
+    context.  This only occurs in the children of blockquote in strict mode.
+</p>
+<p>
+    Example: by default value,
+    <code>&lt;blockquote&gt;Foo&lt;/blockquote&gt;</code> would become
+    <code>&lt;blockquote&gt;&lt;p&gt;Foo&lt;/p&gt;&lt;/blockquote&gt;</code>.
+    The <code>&lt;p&gt;</code> tags can be replaced with whatever you desire,
+    as long as it is a block level element.
+</p>
+--# vim: et sw=4 sts=4