Give e17 a default configuration

This avoids the prompting for configuration at first boot.
Add the epiphany web browser

This is a heavy addition; it brings in many of dependencies. Unfortuantely,
epiphany is the only browser prepackaged in Debian that works at all tolerably
on such a small screen.

In the future, we'll look into Enlightenment's Eve or perhaps Chromium.
Add xterm
Packaging: add changelog entry for 2.3