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 think you're right.  there is a feature enablement which controls whether `FunctionFeed.setEntity` does the `addFeed` call but it defaults to false.  i think i vote in favour of the API adding it explicitly, as is done for enrichers etc.  (but for true API parity we'd have `Spec` classes.)  wdyt?

without this it will work the first time but will not get updated on rebind.