Add Forward function to Horde vacation

Recently , I have several users talked to me that they want to set a forward Email address when they enable vacation in Horde IMP webmail . It looks like recent version of vacation does not have this feature , so I added that to it manually.

vacation module version 1.5 , and source files required to edit are :

vacation/main.php , vacation/templates/main/main.inc, vacation/lib/Driver.php and vacation/lib/Driver/forwards.php

The forward Email Address is restricted to be 35 characters in length.