Stateful version of plugin

[mwraith]

Hi

This is not an issue, but I just wanted to thank you for writing this plugin and let you know that I made an adaptation at mwraith/homebridge-somfi-blinds that uses more of a stateful on/off interface rather than Up/Down/My. Obviously it has the limitation that it will get out of sync if you use the physical remote, but if you don't then it does appear nicer in HomeKit as you can tie it to scenes and therefore ask Siri to "open blinds" etc.

I rewrote several parts of it, but still your contribution saved me so much time particularly around the waveform generation so thank you!