This is a workaround for bug 404184, where KDirWatch only emits
a 'deleted' signal during a 'git stash' workflow, which never
gets paired by a 'created' signal, even though the file actually
exists before and after the 'git stash' operation.

By delaying the handling of the KDirWatch signals, we won't fall
into the trap of removing a file even though it actually exists.
Since it doesn't really matter how fast we react on such events,
it's in my opinion fine to delay it for a full second. Having a
correct state is much more important than having any state fast.

Without this patch, KDevelop frequently forgets about files from large
projects I work on after a `git stash`. This then fubars the C++
support completely, since it cannot find any include paths and
defines anymore.