Bug with RegEx checkbox

Hi,

There is an error in the PHP code that leaves $regex wrongly unset and causes a PHP error.

In file real-time-find-and-replace.php changing

if(isset($farsettings['farregex'][$key]))
  $regex = 'CHECKED';

to

if(isset($farsettings['farregex'][$key]))
  $regex = 'CHECKED';
else
  $regex = '';

fixes the issue

https://wordpress.org/plugins/real-time-find-and-replace/