Javascript to encode / decode email addresses uses deprecated 'unescape' function

[jcogs-design]

Description of the problem
The methods that encode email field type addresses ({encode} and {email_address:mail_to ... } make use of the javascript unescape function.

This function is deprecated in favour of the decodeURIComponent function.

Solution
It should be possible to simply replace the deprecated method with the modern replacement in the embedded javascript (which is set in ft.email_address.php).