Change list sync interval

Set sync interval for change list
GerritService now can accept an option to force refresh, bypassing the SyncProcessor's isSyncRequired method
SyncTime now uses query to determine the last sync time (syncing for open changes is different from merged or abandoned changes)
CardsFragment: Do not set the url when changing projects or (un)stalking a user, this is done by the loader (as we will have all the necessary data in the database)
DatabaseTable: Add general isEmpty method, more commenting
GerritURL: Remove bracketing (should no longer be needed)
SyncProcessor: Added doPostProcess method for setting the last sync time and bookkeeping stuff

Change-Id: I29b36e01d88af7a63b88d0bc3b383ead06794167