Pynsq

* 254 - don't violate max-in-flight on new connections

* 244 - tornado 6.x support, co-routine message handlers
* 247 - switch to GitHub Actions for CI
* 243 - reduce RDY updates when value hasn't changed (thanks andyxning)
* 232 - tornado 5.x support
* 238 - enable IPV6 support (thanks andyxning)
* 230 - fix RDY handling when reducing `max_in_flight` (thanks alpaker)
* 227 - better pydocs for methods

* 223 - update default TLS version to 1.2 and support overriding via tls_options (thanks duczen)
* 219 - fix py.test deprecated parameterization
* 217/218 - python 3 fixes (`mpub`, `AsyncConn`)
* 214 - remove python 2.6 support
* 216 - update PyPI address in docs (thanks aaronjheng)
* 212 - fix python 3.7 `async` keyword conflict
* 211/213/220/225 - misc test/CI related fixes
* 210 - fix snappy/deflate high CPU load on disconnection (thanks zexxonn)
* 208 - fix sending snappy/deflate compressed data (thanks SpaTmole)
* 201 - specify tornado version in setup (thanks jphines)
* 200 - update URL for NSQ protocol in docs (thanks mecforlove)

* 195 - compatibility with tornado 4.5 (thanks ayamnikov)
* 189/192 - address Python deprecation warnings (thanks misja)
* 188 - add ability to specify custom hostname (thanks andyxning)
* 183 - ensure per-connection RDY counts are updated when connections change (thanks alpaker)
* 184 - fix zero delay to time_ms in Message.requeue() (thanks checkraise)

* 177/179 - improved RDY handling; don't decrement RDY; prevent edge case max in flight violations (thanks alpaker)
* 175/176 - prevent edge case max in flight violation (thanks alpaker)
* 174 - ensure that writer only publishes to active connections (thanks panaetov)

* 167/168 - make forwards compatible nsqlookupd queries for NSQ v1.0.0-compat
* 169 - send forwards compatible IDENTIFY attributes for NSQ v1.0.0-compat
* 170 - enable TCP_NODELAY on connections (thanks protoss-player)