Homebridge shelly buttons not working correctly
**Describe your problem**
Hi,
I installed your plugins to drive different Shelly accessories (Shelly 1, Shelly 1PM and Shelly EM3) from HomeKit. 
But my problem is the following:
Homebrige detected well the different Shelly devices available except the EM3 (!?), HomeKit also detected and installed them in Home app. But when I drive an accessory from Home, Homebrige receives the information and seems to react correctly (device switched on or off), but not the Shelly application and therefore the device does not respond. Idem, if I drive an accessory from the Shelly application, neither HomeKit nor Homebrige respond (no reaction). 
What did I do wrong?
Subsidiary question : all my shelly devices have different IP adresses. But the plug-in allows to specify only 1 IP address. How can I specify each IP address (especially when the web access is secured by user/password) ?

**Describe what you have tried so far**
- installed Homebridge-shelly plugin with no argument : working, the shelly devices appear in Homebridge and HomeKit, but no effect when switching them on or off
- personalized plugins : specified one device (Shelly 1PM) with user/password, and its IP address : no better result

**Environment:**
 - Shelly device(s): 1 device Shelly 1, 2 devices Shelly 1PM and 1 shelly EM3
 - Plugin version: 0.19.1
 - Device running homebridge: Raspberry Pi
