ADded j1939 spn definitions in node 
Added Muxed parsing definitions. 
added label definition of signals
renamed factor to scale to adhere to j1939 standards 
Added units definitions from the database included in signals. 
included interval messages for auto cyclic message definitions 
Mux Send msg call send( "MESSAGEID.0x[MUX]" )
chagned .length to .len ( less ambiguous )