bird4: initial commit

this is mainly the bird6 modules slightly adapted to bird4.
tested, but production usage has to show if everything works
bird4: also exchange routes from dn42 and chaosvpn locally
bird4: do not add route to local mesh to table 42

as this interferes with the route added by the post-up
script of the mesh interface
bird4: remove additional blank line from generated local config
bird4: add new parameter depicting the whole ipv4 range of a community

as this might be different from the range used in the mesh. e.g. in hamburg
we use a /18 in the mesh whereas our range is /16.
bird4: update readme
bird: rename bird to bird4
bird: add common ressource for bird4 and bird6
icvpn: initial commit

use this if you want to have icvpn. ipv4-only or ipv6-only icvpn is impossible for the moment
bird6: rename files to avoid conflicts
icvpn: update readme
Remove hard bird dependency

bird or bird6 can now be excluded system wide via ffnord::params
bird6: correct a small dependency
Merge pull request #31 from ohrensessel/add-bird4

bird4: initial commit