Add features list and contributors

README.md

@@ -3,6 +3,10 @@ Use Yubico's YubiKey to authentication to Roundcube webmail.
 
 The plugin is known to be working in production with Roundcube version 0.9.1, 0.8 and 0.7.
 
+##Features
+- Support alternative API servers
+- Validation of the token is done via HMAC-SHA1 authentication over HTTPS (with certificate and hostname validation)
+
 # Requirements
 - Curl PHP module with TLS support.
 
@@ -27,17 +31,17 @@ $rcmail_config['yubikey_api_key'] = 'KEY HERE';
 
 5. Test your installation. You're done!
 
-# Security
-Validation of the token is done via HMAC-SHA1 authentication over HTTPS (with certificate and hostname validation).
-
 # License
 GPL2
 
+# Source
+https://github.com/northox/roundcube-yubikey-plugin
+
 # Acknowledgement
 This code is based on work done by Oliver Martin which was using patches from dirkm.
 
-# Source
-https://github.com/northox/roundcube-yubikey-plugin
+# Contributors
+Stuart Henderson - support alternative API servers and some cosmetic tweaks
 
 # Author
 Danny Fullerton - Mantor Organization