fix replication protocol and exec algo Major changes of protocol: - Removed initial_deps, final_deps use only deps. - Use only two message Prepare and Accept for all functionalities. - Use `seq` to determine execution order, but seq is a per-dependency attribute. this simplies recovery. - Ballot now is a per-replica attribute - Simplify proof of recovery. - Describe why we do not need deps_committed in fast-accept-request - previous execution algo has a bug. Now use qpaxos-exec.md Add a python demo `exec-demo.py` to test qpaxos-exec algo Archive incomplete docs: - remove incomplete exec algo exec-update-accumulated. A step in it is not specified. And it is same as qpaxos-exec. - move old replication doc to archive/ there is a bug - archive analogue doc: exec-local-min is the same as qpaxos-exec - archive unproved doc Get-rid-of-seq - remove draft doc exec.md Draft: r5, leveled-quorum, vc-replication, binary-replication, and several other draft

drmingdrmer committed Sep 8, 2020