stop weavedns from complaining when a container has no docker ip
e.g. when it was started with --net=none

weavedns wasn't actually using the docker-assigned ip for anything, so
this change is a simple matter of eradicating it from the code.
s/weaveIP/ip
stop on 'docker run' errors
This broke due to our workaround for
https://github.com/docker/docker/issues/8632, which affects Docker
version 1.3.0 only, so now we refuse to run with that.
Merge branch '233_stop_on_docker_run_errors' into 238_check_docker_version_when_using_dns
check for Docker version >= 1.2.0 when using "--with-dns"
since --dns-search=. is is new in that version
add `weave stop-dns`
and in the process disentangle stopping dns from `weave stop`
document how to configure search across sub-domains
--version -> -v
Merge branch '233_stop_on_docker_run_errors' into 238_check_docker_version_when_using_dns
Merge pull request #244 from rade/233_stop_on_docker_run_errors

LGTM.  Fixes #233
check that weave container has an eth0
since w/o that we get an obscure error.

The most likely cause for not having an eth0 is that the docker daemon
has been configured to disable container networking.
Merge pull request #245 from rade/238_check_docker_version_when_using_dns

Looks good to me.  Fixes #238
Merge pull request #243 from rade/240_dns_without_docker_net

LGTM.  Fixes #240
Merge pull request #247 from rade/235_document_cross_domain_search

document how to configure search across sub-domains
Use full container names when populating weavedns. Fixes #250
Merge remote-tracking branch 'rade/186_stop_dns'
Merge remote-tracking branch 'rade/189_assert_docker_networking'