Add support for network environment switching

[chadrockey]

Original author: rhick...@google.com (September 09, 2011 19:27:46)

Two different text files have to be edited on the netbook when the robot changes IP address. We should write a script with desktop icon to update these on the fly and an auto-detect job watching for changes.

A user in a new environment would follow this workflow:

1. open network to connect to new wifi network
2. double-tap icon on desktop to show user the current IP address of the wifi adapter and then edit the necessary files for them.

On subsequent visits between networks the workflow would be automatic:

1. netbook cron job always looking for network IP changes
2. if wifi automatically hops to a previously known IP is updated necessary files for ROS to perform on the new network.

Original issue: http://code.google.com/p/rosjava/issues/detail?id=43