client: Changing ifcheck to be more robust

- machine friendly formatted output
- ORed error return codes (first not matching hit returns a code)
- make use of refactored structure, comply to if* functions
Merge pull request #136 from pwieczorkiewicz/ifcheck
[compat] ifcfg support for macvlan

fate#315131
Merge pull request #137 from kmroz/kmroz-wicked-gh-macvlan
compat: enable compat suse only, install ifcfg-lo

Added --with-compat allowing to build and install compatibility
features conditionally. Added --with-compat=suse to spec file.
Other types than 'suse' are incomplete, unsupported [L3] and we
install suse specific config files and scripts at the moment.
Install the /etc/sysconfig/network/ifcfg-lo file (fate#316768).
Merge pull request #138 from mtomaschewski/suse-ifcfg-lo

compat: enable compat suse only, install ifcfg-lo
systemd: removed requisite=wickedd from wicked.service

This dependency triggers an automatic wicked.service (network)
restart, when the wickedd.service is restarted (bnc#859801).
systemd: removed requisite from wicked@ example too
addrconf: fixed routes memory leak in lease destroy
client: fixed to free details in compat netdev
macvlan: fixed schema and flag handling (fate#315131)
version 0.5.6
dhcp4: use common dhcp4 prefix for dhcp4 specifics
leaseinfo: fixed index increment and ip-addr format

Append a /prefixlen to IPADDR same as in ifcfg files
(fate#316111, comment 13 and 14).
fix byteswap in ipudp_checksum and checksum_partial

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Merge pull request #139 from olafhering/olh-dhcp-endian-bugs