[Babel-users] Low level rewrite, install filters

[Juliusz Chroboczek]

Mitar, Kosko,

Matthieu has just done a tremendous job of cleaning up the lower layers of
babeld.  One of the effects is that export filters are now known as
install filters, so you say something like

  install ip ::/0 le 0 table 42

I've taken the risk of pushing this patch series into trunk, please test.
If you're using babeld in production and don't need the install filtering
functionality, please stick to the tag babeld-1.6.3 for now.

This will become babeld-1.7.0 at some point.  I might create a 1.6 branch
if it proves unstable.

Please, please, please test.

-- Juliusz