Basic emoncms integration

Provides emoncms with a regular "ping" containing current ip address,
communicates with emoncms "myip" and also a very basic emoncms "hub"
module. dispatcher runtime settings can be set to enable feature using
emoncms = myip or emoncms and the interval is set emoncmsinterval = 3600
for once per hour. Default settings are emoncms = False and
emoncmsinterval = 3600.