Cping

* Minor internal cleanup.

> Upgrade with `pip3 install -U cping`

* Fixed a regression in **v0.1.9** that caused ICMP pings to be misidentified as belonging to a different session and flag the real session's pings as failed.

> Upgrade with `pip3 install -U cping`

* Added command line options to specify the address family (_i.e._ IPv4 or IPv6). By default, this is chosen by the operating system.
* Added a layout option to view the host's resolved address.
* Continue pinging even if "no route to host" is encountered.
* ICMP echo sequence now starts at 0 to be inline with other ping clients.
* Show page number only if there are multiple pages.

> Upgrade with `pip3 install -U cping`

* Improved the accuracy of the results for long-running cPing sessions. This was only ever an issue if you ran cPing for ~11 days straight. Now you can run it for ~31 centuries, if you're so inclined.

> Upgrade with `pip3 install -U cping`

* Added `-v`/`--version` option to display the current version of cPing.
* Some internal cleanup.

> Upgrade with `pip3 install -U cping`

* 2 - Pings are now updated if they were received after having been considered timed-out. Thanks nichols-356 for reporting this.
* Minor cleanup.

> Upgrade with `pip3 install -U cping`