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.
I'm unconvinced this method is pulling its weight. Perhaps the builder should have a method `body(Repeater)` rather than having this extra method here? That could set the name if it did not already have a name.