Alter the header in db.php file so it's not chosen as the first plugin by `get_plugins()`. Fixes the "Invalid header" issue.
Merge branch 'develop'
Mark as 2.5.6
CSS tweaks for QM output when it's shown in an iframe
Replace use of `strstr()` because the third parameter was only introduced in PHP 5.3. Fixes #33
Show deprecated errors in the PHP errors component