[Request] Ability to get the car state

[robvanmieghem]

For a PV project I would like to be able to get the state of the vehicle.
Currently there are mostly actions like setting the charging amps, which is great but getting the state through the SDK would allow me to check if the charging cable is plugged in.
Don't know if that's possible but getting how much the battery is already charged would be a great help too.

[sethterashima]

Closing as a duplicate of #52 (commands are mostly interface-agnostic).