Add capability to set the startup setting of a switch
Similar to the set switch on or off by sending the required json to the appropriate url it's possible to set the switch default power on setting.

@bwp91 ,
Any way to directly email you directly, I have been using [ewelink-api](https://github.com/skydiver/ewelink-api) and ended up doing a couple of hacks to not have to rely on the WAN and really just operate locally. I wrote a filter to parse tcpdump output, wasn't aware of the node-dns-sd package at the time.

I'm not really wanting to install homebridge for my application but I'd like to be able to use your code so I'd possible like to make some suggestions to make the code a bit more stand-alone or at least include some code to make it possible to use as a library and not just as a homebridge plugin.

I only use the cloud to install and update the devices and then operate locally.

--
Steve