Use eth0 to serve for DHCP clients instead of eth1.

This allows DreamPlugs to work smoothly.  eth0 is used as a DHCP
server for incoming (downstream) clients and eth1 is a DHCP client for
an outgoing (upstream) server.  Now, the dnsmasq server interface is
correctly eth0: otherwise, we'd try to send outgoing packets back to
the client, who'd reject it.

: (computer) -> eth0 -> (dnsmasq) -> eth1 -> (Internet)

eth1 is the outer Ethernet port on a DreamPlug.
Merged from upstream.
Drop freedombox-privoxy from package list to install.  freedombox-setup is enough now.
Reverse roles of eth0 and eth1 ports.

Now:

- 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.

All devices will be DHCP clients on eth0 so all devices can connect
upstream, to the Internet and other FreedomBoxes.  Only devices with
an eth1 port will be able to act as routers.
Merge https://github.com/NickDaly/freedombox-setup
Document change.
releasing version 0.0.34
Update the package description.