1.5.2

CHANGES:

• BUGFIX policy (vmm_resources): when inserting a policy, check policies above,
  but not the same one (@hannesm)
• tls-endpoint: listen on systemd socket, add systemd example (#119 @Julow
  @reynir)
• albatross-stats systemd service: allow AF_NETLINK to gather network interface
  statistics (@reynir)
• BUGFIX albatross-stats: use if_nametoindex, simplify code (#125 @dinosaure
  @reynir @hannesm)
• Add deployment scripts for nixos (#120 @Julow)