Email verification code (#1382)

* Base verification code implementation, must define command, manager, events
* VerificationManager, verification command and messages, handled some sensible commands, configuration values
* Improved manager and sensible commands trigger
* Updated messages
* Updated verification code manager, fixed tests
* Switched to a permission based command
* Verification manager and command improved and added tests
* Edited messages

src/main/java/fr/xephi/authme/permission/PlayerPermission.java

@@ -63,7 +63,12 @@ public enum PlayerPermission implements PermissionNode {
     /**
      * Permission to use to see own other accounts.
      */
-    SEE_OWN_ACCOUNTS("authme.player.seeownaccounts");
+    SEE_OWN_ACCOUNTS("authme.player.seeownaccounts"),
+
+    /**
+     * Permission to use the email verification codes feature.
+     */
+    VERIFICATION_CODE("authme.player.security.verificationcode");
 
     /**
      * The permission node.