Fix bug involving autoclose and inline elements in strict <blockquote>.

The newest autoclose code uses the elements property in whether or not an
element should be closed by a particular tag.  The heuristic is simple; if
the element doesn't allow that tag as a child, it closes the parent
container.  This doesn't work, however, with <blockquote>, which while not
allowing inline styles under Strict doctypes, requires them to be passed
through MakeWellFormed.

The fix was to transition MakeWellFormed to call a method to retrieve the
elements, and then have StrictBlockquote implement a special version of
this method.  Future versions of HTML Purifier may be more flexible in this
regard--further study of the HTML5 specification is required.

Signed-off-by: Edward Z. Yang <edwardzyang@thewritingpot.com>

tests/HTMLPurifier/Strategy/MakeWellFormedTest.php

@@ -93,5 +93,14 @@ class HTMLPurifier_Strategy_MakeWellFormedTest extends HTMLPurifier_StrategyHarn
         );
     }
     
+    function testBlockquoteWithInline() {
+        $this->config->set('HTML', 'Doctype', 'XHTML 1.0 Strict');
+        $this->assertResult(
+            // This is actually invalid, but will be fixed by 
+            // ChildDef_StrictBlockquote
+            '<blockquote>foo<b>bar</b></blockquote>'
+        );
+    }
+    
 }