addnodes support

we just need to add one line to your config.cfg file like:

addnodes=a.b.c.d e.f.g.h i.j.k.l w.x.y.z
Merge pull request #11 from daedalus/master

addnodes support
addnodes support
Merge pull request #12 from daedalus/master

I forgot a small sanity check