Update SMTP.php

remove sensless version_compare(). Min PHP Version is 5.2.1 so is a check of PHP 5.1.0 sensless. So never occurs.
Update Socket.php

remove sensless version_compare(). Min PHP Version is 5.2.1 so is a check of PHP 5.1.0 sensless. So never occurs.
Update rcube_imap_generic.php

remove sensless version_compare(). Min PHP Version is 5.2.1 so is a check of PHP 5.1.0 sensless. So never occurs.
Update SMTP.php
Update Socket.php
Merge pull request #100 from Dennis1993/patch-8

Remove sensless version_compare()
Ignore Reply-To when replying to own message (#1489230)