Fixed a bug with installing opendkim (#1)

The main command for generating DKIM keys (`opendkim`) wasn't installed with just the `opendkim` package.  Added a fix so it would be installed should it not be there the first time `apt` is ran.

emailwiz.sh

@@ -17,6 +17,8 @@
 
 echo "Installing programs..."
 apt install postfix dovecot-imapd opendkim spamassassin spamc
+# Install another requirement for opendikm only if the above command didn't get it already
+[ -e $(which opendkim-genkey) ] || apt install opendkim-tools
 domain="$(cat /etc/mailname)"
 subdom="mail"
 maildomain="$subdom.$domain"