option for 'listener only' to reduce api calls

[luxiouronimo]

i want to be able to run multiple instances of this module without each one calling the weather api individually

• add a 'listener only' option or something that doesn't need an api key (or lat/lon, units, etc)
  • this could want multiple channels to broadcast & listen on, which might indeed fix the ability to use different units in subsequent instances, but this is not a priority
• change processing to accommodate highest common denominator
  • each instance needs to iterate their own max, since they will be provided more than they need, and can't just iterate all

[luxiouronimo]

this is in dev and appears to be working, will publish a v2.0 after a cpl more todos