Networking fixes

Fix potential deadlock on node table update

Squash more warnings

dev/test/build tools to separate crate

Back to original slab crate

Better user errors.

Conflicts:
	util/Cargo.toml
	util/src/lib.rs

UDP Discovery

update readme with rust override

Secret store (part2 - encrypted key/value svc)

fixed warnings on rust beta

Fixed up README.

Kill bad test.