Add make switch command

Simplify quorum threshold rule.

Instead of Bobtail's mean average rule we now simply count votes.

Other changes:

- avoid check-in of patch files
- define dependencies dune-project
- fix ocamlformat version 0.12
- revise static executable build
- rename latency/bandwidth to delta_vote/delta_block.
- improve shutdown behaviour

Simulate smaller latency for votes.

Initial commit: https://arxiv.org/abs/1907.13531 [v1]