This reverts commit d2054269

QfqController.php: E_NOTICE Errors are by default not catched by T3. For QFQ E_NOTICE will throw exceptions from now on
report/Log.php: unused variables commented out.
report/Variables.php: more detailed isset check.
AbstractBuildForm.php: rendering of 'subrecord delete links' broken if column 'id' is missing. Code, which switches from 'id' to '_id' have been already prepared, but was not completely implemented. Exception if neither 'id' nor '_id' exist in subrecord query.

Report.php, Store.php, QuickFormQuery.php: configuration option 'SESSION_NAME' removed and hard coded to 'qfq'.
Session.php, Sip.php: function checkFeUserUid() moved from Sip to Session. Will be called by using 'Session'. SIP's now stored one level deeper in $_SESSION['qfq'][...]. This makes it easier to destroy the SIP cachae in case of login/logout. Destroying the whole $_SESSION var is not a good idea.