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/TwitterBridge.php

@@ -171,7 +171,7 @@ class TwitterBridge extends BridgeAbstract {
 
 			// remove 'invisible' content
 			foreach($tweet->find('.invisible') as $invisible) {
-				$invisible->remove();
+				$invisible->outertext = '';
 			}
 
 			// Skip protmoted tweets