Orkney update

Resource/orkney/add_signals.csv

+SITE_CODE,ADDSTAT_ID,CHANNEL_NAME,SIGNAL_TYPE,HEIGHT,HEIGHT_LOWER,DESCRIPTION
+orkney,30138,press,baro,1.5,1.5,Atm. pressure; h=1.5m
+orkney,30139,rain,rain_o,1,1,Rain detection (0/1)

orkney.md

@@ -30,6 +30,8 @@ NA
 
 1. [List of mast signals](./Resource/orkney/mast_signals.csv)
 
+2. [List of additional signals](./Resource/orkney/add_signals.csv) Note: The statistics for these signals are only included in the header of the packed ASCII file.
+
 ## Nominal values
 
 ![](./Resource/orkney/nom_speed.gif)