QFileWatcher is only reporting one path per signal which is suboptimal if
you change many files at once. This patch is introducing a timer which is
waiting some time time to see if more path changes are reported and is
collecting them in a vector.
Change-Id: I50f7c21186353b199634e7b3cd5a41f8d581a31d
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>