Revert "all: Use ->remove() instead of ->outertext = ''"

This reverts commit 052844f5e1.

There is a bug in ->remove() that causes the parser to incorrectly
identify elements in the DOM tree that shouldn't exist anymore.

References #1151

bridges/FacebookBridge.php

@@ -584,7 +584,7 @@ EOD;
 
 						foreach($content_filters as $filter) {
 							foreach($content->find($filter) as $subject) {
-								$subject->remove();
+								$subject->outertext = '';
 							}
 						}