4980 / Variables in Report: a) nested not replaced, b) 'rbeg' not replaced, c) missing unit tests.

Report.php: 'line.count' general available per row. 'line.insertId'. RBGD moved inside of processing result. Replace variables in RBEG.
Variables.php: RegExp changed from 'all variables in double curly braces' to 'line.varname' - the other variables are replaced in eval.
Evaluate.php: Fixed problem that 'Dropdown Select' with '{{! SE...' not recognized.