Brooklyn node and cluster upgrade

Merges #266 (cluster upgrade) with work I've been doing on node upgrade.

Builds on #260 so please ensure that is merged first.

Needs further testing (by me at this point) but wanted to push it in case @neykov you have comments, especially on the last commit.
Gut feel is that something more like the expects in a mock would be cleaner to use. Or caller could list the expected calls in order, and the response for each.

But no strong feelings. This looks fine.