- added 'kvm' group to CLONE_GROUPS variable;

- introduced TMPDIR variable to assist (user-defined prefix) the mktemp command. However, we should make sure that in rescue mode the TMPDIR variable is unset so the mktemp creates the BUILD_DIR under /tmp/rear.XXXXX (issue #323 and #157). By setting TMPDIR in local.conf we can choose were the BUILD_DIR resides (as it also contains the large ISO image);

- when we backup to ISO image make sure that the isofs module is copied to the rescue image (issue #326)