affile: poll-file-changes refactor

Signed-off-by: Budai Laszlo <lbudai@balabit.hu>
filemonitor_poll: read the whole directory in every poll cycling,

because it takes too much time to step file-by-file
in case of lot of files and large follow-freq number.

Signed-off-by: Juhász Viktor <jviktor@balabit.hu>
affile: path resolving replaced by a realpath() based implementation

Signed-off-by: Budai Laszlo <lbudai@balabit.hu>
affile: enable inotify in configure.ac

Signed-off-by: Budai Laszlo <lbudai@balabit.hu>