Eider

* support `msg` param to `Future.cancel` in Python 3.9+ (`TypeError: RemoteCall.cancel() takes 1 positional argument but 2 were given`)

* add support for Python 3.8-3.11
* drop support for Python 3.4-3.6
* no changes to Eider protocol; fully compatible with eider 1.x over the wire
* switch from Travis CI to Circle CI

* rename `forEachAsync` to `forAwait` and support early termination ed9da89
* drop support for [uws](https://www.npmjs.com/package/uws) 6a287c9
* bump dependency versions
* other minor housekeeping

* fixed minor marshalling bugs
* support for asynchronous context managers in `using()`
* improved wait semantics and error propagation when using connection as a context manager
* made `createSession()` asynchronous

* Added automatic direct property access f9fac3eb872f2891448dc57dc7e607fdda453265
* Allow choice between [uws](https://www.npmjs.com/package/uws) and [ws](https://www.npmjs.com/package/ws) f083a045abe65aadd8ee3f3e56ee70e2c0f2e526
* Fixed serialization of undefined object members 2e50627db04bbe4a67c843375a23b9a908ddb422
* Defend against Object.prototype monkey-patching 6c4ee9030a7b8f0e082c5f9682ef4fd4cda2235e

* Fixed reference-cycle bug in LocalObjectBase::_close 3960dad2585c55d08b2574a9be7eb535f33be7b6
* Added LocalSession magic to enable proper two-stage initialization of LocalObjects 3960dad2585c55d08b2574a9be7eb535f33be7b6
* Rewrote test suite to verify object lifetimes and provide more realistic example 4dd53af5895253243e9afd9b781aa5add5b43ce4