add 'weave start'
add usage
Merge pull request #150 from rade/126_weave_start

LGTM.  Closes #126, also referenced from #148
drop IP/network from 'weave launch'
plus a whole bunch of other small changes to weave script which I'll
eventually extract into separate commits.
fix 'weave start' post rebase
Merge branch '130_launch_without_ip' of github.com:rade/weave into 130_launch_without_ip

Conflicts:
	weave