Dispatcher default settings

Dispatcher defaults added so that if no "url" specified in emoncms
dispatcher it will default to emoncms.org. localhost address is set
ready for local install or just delete or edit url string for
emoncms.org account. If apikey is not set (ie 4 or more x's or omitted)
dispatcher will not send (but it will still acumulate data in buffer
until apikey changed. emonCMS defaults to a max of 100 items per post
which can be overridden.
emonhub.conf has been reduced some more and now only has a single
"emonCMS" dispatcher and a single "RFM2Pi" listener.