Add sign-in and token retrieval to Blimp

blimp/client/android/AndroidManifest.xml.jinja2

Index: blimp/client/android/AndroidManifest.xml.jinja2
diff --git a/blimp/client/android/AndroidManifest.xml.jinja2 b/blimp/client/android/AndroidManifest.xml.jinja2
index 3d353311a51cc22ade2b91aa871c72a0a000e88a..2f58abee731ce23721384908c7d833fb6ee7e560 100644
--- a/blimp/client/android/AndroidManifest.xml.jinja2
+++ b/blimp/client/android/AndroidManifest.xml.jinja2
@@ -10,6 +10,7 @@
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
     <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
     <uses-permission android:name="android.permission.INTERNET"/>
+    <uses-permission android:name="android.permission.GET_ACCOUNTS"/>
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
     <application android:name="BlimpApplication"
             android:label="Blimp">
@@ -23,5 +24,8 @@
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
+
+        <meta-data android:name="com.google.android.gms.version"
+                android:value="@integer/google_play_services_version" />
     </application>
 </manifest>