Implement authentication detection

* pending command to see which instances have never authenticated
* authcheck command to see which instances are not currently
  authenticated

conf/example/irc.json

@@ -2,8 +2,12 @@
     "_": {
         "register": true,
         "entity": "NickServ",
-        "email": "{nickname}@example.com",
+        "email": "{nickname}.irc@domain.com",
         "register": "REGISTER {password} {email}",
-        "confirm": "CONFIRM {token}"
+        "confirm": "CONFIRM {token}",
+        "check": true,
+        "checktype": "mode",
+        "checkmode": "r",
+        "checkmsg": "Password accepted - you are now recognized."
     }
 }