add hasToken method (#351)

* add method to determine whether token exists or we need to re-authenticate

* document on the facade

src/Omniphx/Forrest/Client.php

@@ -719,6 +719,16 @@ public function getToken()
         return $this->tokenRepo->get();
     }
 
+    /**
+     * Determine whether token exists
+     *
+     * @return bool
+     */
+    public function hasToken()
+    {
+        return $this->tokenRepo->has();
+    }
+
     /**
      * Returns any resource that is available to the authenticated
      * user. Reference Force.com's REST API guide to read about more

src/Omniphx/Forrest/Providers/Laravel/Facades/Forrest.php

@@ -8,6 +8,7 @@
  * @method static \Illuminate\Http\RedirectResponse|void authenticate()
  * @method static void refresh()
  * @method static \Psr\Http\Message\ResponseInterface|void revoke()
+ * @method static bool hasToken()
  * @method static void setCredentials(array $credentials)
  * @method static string|array versions(array $options = [])
  * @method static string|array resources(array $options = [])
@@ -55,7 +56,7 @@
  * @method static string|array actions(string $resource, array $options = [])
  * @method static string|array support(string $resource, array $options = [])
  * @method static \Omniphx\Forrest\Interfaces\RedirectInterface callback()
-*/
+ */
 class Forrest extends Facade
 {
     /**