Whitelisting is now supported by all nodes that support signing, while only nodes that define a whitelist with MY_SIGNING_NODE_WHITELISTING will check signatures against a whitelist. This allows a single node in a network to have a whitelist without require all nodes that communicate it to be configured for whitelisting. The node will publish its whitelisting preferences to the gateway together with its signing preferences. In other words; whitelisting is now working as signing requirements does. A node that use whitelisting will reject any message (signed or unsigned) from nodes not present in its whitelist. Fixes #279
For information on installing libraries, see: http://arduino.cc/en/Guide/Libraries