State channel support

- Add dc_payload_size var to sc test

Do not embed quay robot password (derp)

remove sync swarm TID lookups

Build miner inside Docker container for aarch64

Target arm64v8 architecture

WIP: Buildkite

BK path error

Make sure qemu-static is available

Fix up docker build

Fix up bash start

Make sure we copy our runner into the binary

Full path to bin

Mount qemu in Docker build

Test multiplatform build

Attempt 32 bit build too

Remove heroku.yml

plug holes in seen tracking

plugging a different hole in the hbbft state machine opened up one
with seen tracking that caused a lot of votes to be discarded.  while
debugging, I noticed bba and seen data is not zeroed out in a skip.

Add tests for witness refresh

Prepare for 2020-04-27

Dependent transaction tests

Fix blockchain_SUITE's election test

Relax poc receipt submit timeouts and track transactions via callbacks

If the submitting node is not more than 5 blocks behind the chain it
will never see its poc request hit the chain and thus end up in a loop
of never submitting receipts. This lengthens the poc request submission
timeout to the same as the poc interval and uses the transaction
callback to log if the receipt has been submitted.

Optionally mirror all packet forwarder up/down packets to a seperate udp socket

bump to latest blockchain core.  Fixes to account for txn mgr using records and txn list response as maps. Tweak some test timers