Fix README formatting.

Change mDNS record to note TLS support. (WebThingsIO#75)

Support new zeroconf version. (WebThingsIO#73)

Fixes WebThingsIO#72

Update CHANGELOG.

Update workflows.

Update version and changelog.

Update changelog.

Switch from netifaces to ifaddr. (WebThingsIO#50)

ifaddr is pure Python, so it doesn't require a toolchain like
netifaces does.

Handle tornado 6.X versions. (WebThingsIO#47)

Fixes WebThingsIO#46

Add support for Python 2.7 and 3.4. (WebThingsIO#41)

Fixes WebThingsIO#40