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/CastorusBridge.php

@@ -58,7 +58,7 @@ class CastorusBridge extends BridgeAbstract {
 			returnServerError('Cannot find nodes!');
 
 		foreach($nodes as $node) {
-			$node->remove();
+			$node->outertext = '';
 		}
 
 		return strtotime($activity->innertext);