Implement Internet Explorer compatibility code for embedded content.

Signed-off-by: Edward Z. Yang <ezyang@mit.edu>

library/HTMLPurifier/ConfigSchema/schema/HTML.SafeEmbed.txt

@@ -7,8 +7,7 @@ DEFAULT: false
     Whether or not to permit embed tags in documents, with a number of extra
     security features added to prevent script execution. This is similar to
     what websites like MySpace do to embed tags. Embed is a proprietary
-    element and will cause your website to stop validating. You probably want
-    to enable this with %HTML.SafeObject.
-    <strong>Highly experimental.</strong>
-</p>
+    element and will cause your website to stop validating; you should
+    see if you can use %Output.FlashCompat with %HTML.SafeObject instead
+    first.</p>
 --# vim: et sw=4 sts=4

library/HTMLPurifier/ConfigSchema/schema/HTML.SafeObject.txt

@@ -6,9 +6,8 @@ DEFAULT: false
 <p>
     Whether or not to permit object tags in documents, with a number of extra
     security features added to prevent script execution. This is similar to
-    what websites like MySpace do to object tags. You may also want to
-    enable %HTML.SafeEmbed for maximum interoperability with Internet Explorer,
-    although embed tags will cause your website to stop validating.
-    <strong>Highly experimental.</strong>
+    what websites like MySpace do to object tags.  You should also enable
+    %Output.FlashCompat in order to generate Internet Explorer
+    compatibility code for your object tags.
 </p>
 --# vim: et sw=4 sts=4

library/HTMLPurifier/ConfigSchema/schema/Output.FlashCompat.txt

@@ -0,0 +1,11 @@
+Output.FlashCompat
+TYPE: bool
+VERSION: 4.1.0
+DEFAULT: false
+--DESCRIPTION--
+<p>
+  If true, HTML Purifier will generate Internet Explorer compatibility
+  code for all object code.  This is highly recommended if you enable
+  %HTML.SafeObject.
+</p>
+--# vim: et sw=4 sts=4