* fix authenticating server example

* certificate handling working, tests required

* add tests

* add example certificates and remove some useless code

* add client-with-encryption.py to connect with server-with-encryption

--amend

* Add async and await to get_namespace_array methods
Add /venv to gitignore

* Removed Coroutine typing from get_namespace_array methods

This fixes the second problem described in https://github.com/FreeOpcUa/opcua-asyncio/issues/160#issuecomment-622985985

This fixes the first problem described in https://github.com/FreeOpcUa/opcua-asyncio/issues/160#issuecomment-622985985

Fix exception when disconnecting while not all Requests were processed.

This reverts commit 9ed0ca4b.

This reverts commit 99ee95d9.

Fixed comparison with literal. Comparision with a literal (str) should always be "!=" and not "is not".