Iteration on display groups UI, was neglected for awhile.

Switched to using Accounts metadata provided through
Sources cache.  Also added long-press and menu item to serve
as our "edit sync groups" in the same UI.

Need to iterating to show all accounts regardless of group
existance, and persist DEFAULT_SHOULD_SYNC values.
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 6a005a0..f77a7bb 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -233,7 +233,7 @@
             />
         </activity>
 
-        <activity android:name=".DisplayGroupsActivity" android:label="@string/displayGroups" />
+        <activity android:name=".ui.DisplayGroupsActivity" android:label="@string/displayGroups" />
 
         <activity
             android:name="ShowOrCreateActivity"