CAT 2.0.0 RC2

* Added compatibility with many older Macs when using a USB Bluetooth
4.0 dongle (see chart).
* Added the ability to choose the admin user executing the tool
[#14](https://github.com/dokterdok/Continuity-Activation-Tool/issues/14)
* Added new diagnostics, including a system wide Continuity activation
check.
* Added ability to run the System Diagnostic from the command line
without admin privileges.
* Improved the command line execution and arguments.
* Improved the layout and diagnostic messages accuracy.
* Fixed an issue where OS X kext protection wasn’t disabled is some
cases, leading to a loss of Wi-Fi / Bluetooth connectivity.
* Minor optimisations and bug fixes.