New Icons by egeant94 (#4)

* Delete lhv2_off.ico, lhv2_off.svg, lhv2_on.ico, lhv2_on.svg
* added credits section for icons to `README.md`
* added new icon files by egeant94

Minor bug fix

Update lighthouse-v2-manager.py

- added MAC address format checking
- simplified command line handling
- added option to automatically create Desktop Shortcuts for both the python script version and the binary stand-alone version
- added more descriptive text output and error messages

Create lighthouse-v2-manager.py