Makefile no longer saves/restores previous image details.

Since we don't actually do anything with the architecture, machine,
and destination we save from the environment, just forget them.
Remove unused "STAMP" variable.
Updated documentation to reflect FBX-Setup changes.

In FBX-Setup, we re-purposed the eth0 and eth1 ports:

- eth0 :: DHCP client (connects to router).
- eth1 :: DHCP server (connects to end-device).

This allows all targeted hardware to connect to the Internet without
issue, whether or not they have an eth1 port.
Merge remote-tracking branch 'pere/master'