Deprecated execute function on single clients, updated changelog (#403)

* Deprecated execute function on single clients
* Added test
* Updated changelog

Upgrade (#398)

* Fixed issue with stdin flush for libssh clients
* Updated changelog
* Updated sshd template
* Updated versioneer
* Updated logging
* Refactored tests, imports
* Updated CI cfg
* Updated docstrings
* Updated imports
* Updated readme
* Prettify tests

Upgrade (#398)

* Fixed issue with stdin flush for libssh clients
* Updated changelog
* Updated sshd template
* Updated versioneer
* Updated logging
* Refactored tests, imports
* Updated CI cfg
* Updated docstrings
* Updated imports
* Updated readme
* Prettify tests

Perf changes (#357)

* Performance improvements for reading output in all clients.
* Output reading for all clients has been changed to be less prone to race conditions.
* Parallel clients now read a common private key only once, reusing it for all clients it applies to, to improve performance.
* Updated changelog.
* Added test case for joining on parallel clients without ever running run_command. Updated join so that it does not raise exception in that case.

Fixed race condition with native clients when global timeout setting … (

#353)

* Fixed race condition with native clients when global timeout setting is used and running short lived commands.
Resolves #344.
* Updated changelog
* Updated default log formatter set by `pssh.utils` enable logger functions.

Bumped minimum dependency versions (#350)

* Bumped minimum dependency versions
* Updated CI cfg
* Updated changelog

Updated CI cfg (#352)

* Updated CI cfg

Updated CI cfg (#351)

Host config (#342)

* Updated clients for getting all configuration entries from host config
* Updated changelog, documentation
* Updated tests
* Added bytes support to proxy_pkey, added test - resolves #338
* Updated RTD configuration
* Updated setup.cfg
* Updated CircleCI cfg
* Updated copyright notices

More scp_send race condition fixes (#341)

* More scp_send race condition fixes - resolves #337
* Updated changelog