simplify error handling

* less convoluted exception dialogs
* use window.onerror for the majority of exception catching/reporting
* remove most of now useless try/catch blocks
* report stacktrace instead of manually specified error locations

include/functions2.php

@@ -1902,7 +1902,7 @@
 			WHERE owner_uid = '".$_SESSION["uid"]."' ORDER BY caption");
 
 		print "<select default=\"$value\" name=\"" . htmlspecialchars($name) .
-			"\" $attributes onchange=\"labelSelectOnChange(this)\" >";
+			"\" $attributes>";
 
 		while ($line = db_fetch_assoc($result)) {