when granting a range that spans a token and inserting a new token, the
free space on the last token that we are handing over has to change.
Add unit test for this too.
- removed detailed "free" and "owned" printout of 'space'
- removed "free" counts from ring lines - limited usefulness and often out of date.
- removed trailing newline
- changed "Ring" to "Owned Ranges"
- print subnet in CIDR format
Using the Ring CRDT and Weave gossip, provides an interface
for the weave script to allocate IP addresses in `weave run`,
`weave start` and `weave expose`.
See docs/ipam.md for implementation details, and site/features.md
for user-visible changes.