Support for multiple Powerboards on a module.

The PBV3TBModule definition in a configuration file now requires a pbs list defining the available Powerboards. The available keys for each Powerboard are:

• idpads: Value of the bonded padID
• commid: Target CommID to be set.

For example, a BETSEE is configured as:

{
   "testbenches":{
      "default":{
         "type":"PBv3TBModule",
         "ip":"192.168.222.16",
         "port":60003,
         "pbs":[
            {
               "idpads":4,
               "commid":0
            },
            {
               "idpads":0,
               "commid":1
            }
         ]
      }
   }
}