Add IPv4/IPv6 lookup services

src/example.config.py

@@ -46,6 +46,7 @@ run your own external IP provider:
 + <?php $ip = $_SERVER['REMOTE_ADDR']; ?>
   <?php print $ip; ?>
 e.g. 
++ https://api[4|6].ipify.org
 + https://ifconfig.co/ip
 + http://ifconfig.me/ip
 + http://whatismyip.akamai.com/
@@ -53,3 +54,7 @@ e.g.
 + many more ...
 '''
 ifconfig = 'choose_from_above_or_run_your_own'
+ifconfig = {
+    "ipv4": 'choose_from_above_or_run_your_own_ipv4_lookup_service',
+    "ipv6": 'choose_from_above_or_run_your_own_ipv6_lookup_service',
+}