The QNetworkAccessManager is reset when we are disconnected, just
before attempting to fetch the server's status.php.
This may help fix the problem described in various issues where we
get 'Connection closed' or timeout errors after the OS has woken
from sleep.
* Use a shared pointer to Account everywhere to ensure
the instance stays alive long enough for a sync to terminate
* Folder is now tied to an AccountState
* SyncEngine and OwncloudPropagator tie to an Account and use that
for all jobs they run
Issue: Since the setup wizard currently always replaces the
account, it will always wipe all folder definitions, even when
the actual changes to the account were minor.
This allows all the account state information to live in gui
while the sync-relevant data stays in libsync.
I also moved quotainfo to gui since it depends on the account state.
