Faucet

* Don't send empty apply action instructions
* Add support for VLANs on a stack that aren't expressed on the root switch
* Fix LACP role metric was not updated when stack root changes
* Remove experimental API
* Export ryu_conf variables to as Prometheus metrics
* Gauge now clears all variables on config reload (so de-configured DP variables are removed)
* Update dependencies:
* prometheus 2.20.0 [docker]
* grafana 7.1.1 [apt, docker]
* sphinx 3.1.2 [docs]
* pytype 2020.7.30 [tests]

* Optimization: suppress unneeded overlapping OpenFlow delete messages.
* Do not allow overlapping interface_ranges in configuration file.
* Add a prometheus variable for stack root status by datapath.
* Update dependencies:
* prometheus 2.19.2 [docker]
* grafana 7.0.4 [apt, docker]
* sphinx 3.1.1 [docs]
* sphinx_rtd_theme 0.5.0 [docs]
* pytype 2020.6.26 [tests]

* Optimise out actions that won't have any effect (e.g. modify packet header before dropping it)
* Fix coprocessor traffic being subject to VLAN ACLs
* Move LACP implementation to switch manager classes
* Remove unneeded mininet dependency in unit tests

* Fix package build issue

* Generate fewer unnecessary delete rules updating flood tables
* Fix crash when dot1x enabled but no ports enabled for dot1x
* Fix missing anti-spoofing rule after reload
* Fix incorrect flood table size on larger stacked networks
* Fix not able to have multiple tunnel rules in same ACL
* Fix coprocessor ports not able to have ACL
* Set LACP prometheus variables consistently when port is down
* Unit tests now run on python3.8
* Unit tests can do multiple virtual switches and can generate additional topologies for more test coverage
* Upgrade to latest version of docker in travis environment
* Update dependencies:
* prometheus client 0.8.0 [apt, pip]
* grafana 7.0.3 [apt, docker]
* alpine 3.10.5 [docker]
* sphinx 3.1.0 [docs]
* pytype 2020.6.1 [tests]
* pylint 2.5.3 [tests]
* exabgp 4.2.10 [tests]

* Optimize stack reloading - don't take down stack ports on config restart, unless there was a topology change.
* Update dependencies:
* grafana to v7.0.0 [apt, docker]
* prometheus to v2.18.1 [docker]