Fix KDirWatch so that it has a more uniform behavior whether the backend is inotify or FAM:
the most important change with inotify is that when a file is created in a watched directory, dirty(dir) is emitted rather than created(dir/file), as it has always been before inotify.

created() is for things that have been explicitely watched for.

Many fixes in the FAM support, most taken from the last year of fixes in the inotify code.

Some fixes in the unittest: FAM (well, gamin at least) can't detect the case where /etc/localtime is deleted+recreated immediately; and FAM needs more sleeps in the tests so that it can detect mtime differences.

This makes the test much slower in fam mode (19s instead of 5s), and I'm not sure about some of these delays, to be investigated further.

Linux users can run the unittest in FAM mode with KDIRWATCHTEST_USE_FAM=1; should automate that somehow...