Tplink-cloud-api

* Inform user of failure to get sys_info for device (print message and return `None`)

* Add support for KP303 Power Strips
* Removing async logic until it can be revisited - it wasn't really doing anything asynchronously

The main purpose of this release is to introduce automated testing (which isn't really important for library consumers)

Includes bug fixes for HS103 and HS105 which were not correctly getting action data

Includes non-backwards compatible change renaming the device's `client` attribute to `_client` as it should not be used outside of the library.

Fixed a bug breaking everything - asyncio is built into Python by default so it should not be specified in the `install_requires` as that will break things like lambda functions built to include this library.

Add support for KP115 devices

Adding None checks for HS300 devices that are not reporting correctly.