don't print project messages/warnings/errors

they are meaningless during the cumulative parse we are doing

Task-number: QTBUG-28159
Change-Id: I501e7e9b0066fc3f36543147d71632b0d20cca08
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
don't print warnings from parser & evaluator

they are pretty much noise in lupdate context.
we still print error messages: the ones from the parser are always
genuine, while the ones from the evaluator are at least occasionally
helpful.

Task-number: QTBUG-28159
Change-Id: I6cdb11b51c0a3f569ec430f98a0068f933db903d
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
execute some loops even in cumulative mode

we execute foreach loops now. this is (mostly) safe nowadays, because
a previous change added precautions against exponential value list
growth, so it's unlikely that two nested loops would keep the cpu busy
for a day as before.

we continue to exclude forever loops and loops with excessive integer
counts.

Task-number: QTBUG-8550
Change-Id: Iaa116086986cc7fd5023834753f791dd205102e5
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>