Unit required in sendGroup()

[github-ec]

Just a hint for the use of the NewRemoteTransmitter sendGroup() function:

I'm using remote controlled switches from Smartwaves (SH4-9950HT) sold by the "Action"

https://www.smartwares.eu/nl-nl/smartwares-sh4-99580at-draadloze-schakelaarset-sh4--99580at

and had to change the _sendUnit() value in void NewRemoteTransmitter::sendGroup(boolean switchOn) {} from _sendUnit(0); to sendUnit(15); to successfully switch the states.

I got the information about the required unit value from reading the group command with NewRemoteReceiver.

It might be interesting to implement an additional function void NewRemoteTransmitter:sendGroup(byte unit, boolean switchOn){}; that allows to set the unit when required ...

Anyway, thanks for your great library!
ec2021