Add support for token based api authentication

README.md

@@ -21,10 +21,20 @@ The first step is to instantiate a new instance of the Loggly class:
 
     $loggly->subdomain = '<loggly subdomain>';
 
+Authenticate using username & password
+========================================
+
+
     $loggly->username = 'demo';
 
     $loggly->password = '42ftw';
 
+Authenticate using [API Token](https://www.loggly.com/docs/token-based-api-authentication/)
+==============================
+
+
+    $loggly->apiToken = 'c1f1e7e4-61e7-4b19-83f4-a26dd61dca3c';
+
 
 Input and Device Methods
 ========================
@@ -157,4 +167,4 @@ Support
 =======
 Have questions?
 
-Contact support@loggly.com (please include your subdomain)
+Contact support@loggly.com (please include your subdomain)