Added hotplug script to match AP IP address to thisnode host alias

Closes Issue #34.

To test:
1. Delete 'thisnode' entry in /etc/hosts
2. /etc/init.d/network restart should add a 'thisnode' entry with the node access point's IP address.
3. In /etc/hosts, change the IP address for 'thisnode' to 192.168.1.20
4. /etc/init.d/network restart should update the 'thisnode' entry to the node access point's IP address.