Bump version 0.22.0 -> 0.23.0

bump version v0.21.1 -> v0.22.0

Update setup.py

Update setup.py

bump version 0.19.1 -> 0.20.0

bump version 0.19.0 -> 0.19.1

bump version 0.18.0 -> 0.19.0

bump version 0.17.1 -> 0.18.0

Changed -e to --exec.
More current versions of the openbsd netcat have an -e option.
Changing pync's -e to --exec is to avoid conflict in future versions of pync where I want to implement netcat's -e option.

bump version 0.17.0 -> 0.17.1

* fix issue with parsing -w flag (forgot to return value from argument type).
* Added timeout for client udptest.

bump version 0.16.0 -> 0.17.0