constants: Add new enums for LSB return codes
client: Cleanup return codes

Introducation of a new, common option: --systemd.
This options is supposed to make sure no non-zero return codes
are gave back. To be used with systemd's service files.

Make use of new LSB and ST return code enums.
autoip4: Cleanup return codes

Introducation of a new, common option: --systemd.
This options is supposed to make sure no non-zero return codes
are gave back. To be used with systemd's service files.

Make use of new LSB return code enums.
dhcp4: Cleanup return codes

Introducation of a new, common option: --systemd.
This options is supposed to make sure no non-zero return codes
are gave back. To be used with systemd's service files.

Make use of new LSB return code enums.
dhcp6: Cleanup return codes

Introducation of a new, common option: --systemd.
This options is supposed to make sure no non-zero return codes
are gave back. To be used with systemd's service files.

Make use of new LSB return code enums.
nanny: Cleanup return codes

Introducation of a new, common option: --systemd.
This options is supposed to make sure no non-zero return codes
are gave back. To be used with systemd's service files.

Make use of new LSB return code enums.
server: Cleanup return codes

Introducation of a new, common option: --systemd.
This options is supposed to make sure no non-zero return codes
are gave back. To be used with systemd's service files.

Make use of new LSB return code enums.
fsm: Change default __ni_ifworker_print_tree() print dest

Correct from fprintf(stderr,...) to ni_debug_application()
client: correct quiet mode for ifcheck
Merge pull request #127 from pwieczorkiewicz/return_codes_2