simple cleanups
Merge pull request #356 from claws/fix_zconfig_in_readme

simple cleanups
the real fix
Merge pull request #357 from claws/fix_zconfig_second_attempt

the real fix
zsys_interface: use default value from an environment variable if supplied.
zbeacon: check ifa_flags when scanning interfaces
Merge pull request #358 from mattconnolly/master

zsys_interface: use default value from an environment variable if supplied.
Merge pull request #359 from mattconnolly/interface-detection

zbeacon check ifa_flags to filter list of interfaces
Merge pull request #360 from mhaberler/master

zloop: clarify argument of zloop_timer_end()
libsodium fix as long a it is still broken
Merge pull request #361 from sappo/master

libsodium fix as long a it is still broken
Fix invalid frame memory leak in s_beacon_recv
Merge pull request #362 from m-marsella/master

Fix invalid frame memory leak in s_beacon_recv
zmsg recv no wait extension
Merge pull request #363 from sappo/master

zmsg recv no wait extension
Update zsys.c

the self test forgets to delete the folder ".testsys"
(correct me if I'm wrong)
On my machine, this adjustment fixes the problem.
Merge pull request #364 from MilfordTea/master

Update zsys.c
Fixed issue #366
Whitespace & formatting fixes
Fixed a comment