[3.1.0] Implement DenyElementDecorator for imagecrash-protection against CSS width/height

- Misc doc changes
- Add missing inheritance for AttrDef_CSS decorators


git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1684 48356398-32a2-884e-a903-53898d9a118a

tests/HTMLPurifier/Strategy/ValidateAttributesTest.php

@@ -177,6 +177,13 @@ class HTMLPurifier_Strategy_ValidateAttributesTest extends
         );
     }
     
+    function testRemoveCSSWidthAndHeightOnImg() {
+        $this->assertResult(
+            '<img src="" alt="" style="width:10px;height:10px;border:1px solid #000;" />',
+            '<img src="" alt="" style="border:1px solid #000;" />'
+        );
+    }
+    
 }