Accessibility: add states to QQuickAccessibleAttached

This makes it possible to set the state of accessible objects in qml.

Change-Id: Ide70b885dac8fed180d2b221540cf2b699ac78ff
Reviewed-by: Jan Arve Sæther <jan-arve.saether@digia.com>
Make sure a profiling range is started for every handled signal

If we allow an endRange() without a startRange() before the range
nesting can get confused. Also, it's enough to check the existence
of the profiler once.

Change-Id: I255675d6e23505b6f29196c0470892f6d778e7b4
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>