adding ConsumeOutputOperation

 - With that operation we can save the original qmake output,
   before the installer does the patching. So we can use the old values
   for modules patching if they will be installed later.
 - added a autotest which does that with the current used qmake

Change-Id: Ie07d273bf64d1813b7af3374a0db35a9e1215503
Reviewed-by: Niels Weber <niels.weber@digia.com>
Reviewed-by: Karsten Heimrich <karsten.heimrich@digia.com>
add exceptionhandler code for connected signals/JS methods

 - there wasn't any error information if a C++ triggered signal resulted
   in a JS method which has an error, now it will create an exception for it
 - creating messagebox inside the lib is something what we want to avoid,
   so the developer itself is responsible to catch these exceptions
 - most cases of the installer code does that already

Change-Id: I07486f73be9de13a486de235f14e3a7d7b54f5b1
Reviewed-by: Karsten Heimrich <karsten.heimrich@digia.com>