Release v1.6.0 (#324)

* Update version and changelog for v1.6.0
* Update docs
diff --git a/docs/dyn/dataflow_v1b3.projects.jobs.messages.html b/docs/dyn/dataflow_v1b3.projects.jobs.messages.html
index a33e7cd..86bed2f 100644
--- a/docs/dyn/dataflow_v1b3.projects.jobs.messages.html
+++ b/docs/dyn/dataflow_v1b3.projects.jobs.messages.html
@@ -75,14 +75,14 @@
 <h1><a href="dataflow_v1b3.html">Google Dataflow API</a> . <a href="dataflow_v1b3.projects.html">projects</a> . <a href="dataflow_v1b3.projects.jobs.html">jobs</a> . <a href="dataflow_v1b3.projects.jobs.messages.html">messages</a></h1>
 <h2>Instance Methods</h2>
 <p class="toc_element">
-  <code><a href="#list">list(projectId, jobId, startTime=None, pageSize=None, x__xgafv=None, pageToken=None, minimumImportance=None, endTime=None)</a></code></p>
+  <code><a href="#list">list(projectId, jobId, startTime=None, pageSize=None, x__xgafv=None, pageToken=None, location=None, minimumImportance=None, endTime=None)</a></code></p>
 <p class="firstline">Request the job status.</p>
 <p class="toc_element">
   <code><a href="#list_next">list_next(previous_request, previous_response)</a></code></p>
 <p class="firstline">Retrieves the next page of results.</p>
 <h3>Method Details</h3>
 <div class="method">
-    <code class="details" id="list">list(projectId, jobId, startTime=None, pageSize=None, x__xgafv=None, pageToken=None, minimumImportance=None, endTime=None)</code>
+    <code class="details" id="list">list(projectId, jobId, startTime=None, pageSize=None, x__xgafv=None, pageToken=None, location=None, minimumImportance=None, endTime=None)</code>
   <pre>Request the job status.
 
 Args:
@@ -92,6 +92,7 @@
   pageSize: integer, If specified, determines the maximum number of messages to return. If unspecified, the service may choose an appropriate default, or may return an arbitrarily large number of results.
   x__xgafv: string, V1 error format.
   pageToken: string, If supplied, this should be the value of next_page_token returned by an earlier call. This will cause the next page of results to be returned.
+  location: string, The location which contains the job specified by job_id.
   minimumImportance: string, Filter to only get messages with importance >= level
   endTime: string, Return only messages with timestamps < end_time. The default is now (i.e. return up to the latest messages available).