add script to build and test a series of commits

at Ben's request, I wrote a script to test a series of patches.  He
has some hairy rebasing that needed decent testing before sending the
patch.

To be useful, it should also let the user specify other parameters for
the custom build.
add laura's remotes
debian_installer: install avahi-daemon
debian_installer: assert that /dev/sd* exists rather than ./sd*
debian_installer: dist-upgrade multiple times

For some reason if dist-upgrade is run only once the updates are often
incomplete. By forcing it to run 3 times this problem is (hopefully)
worked around.
debian_installer: update login for creating 32bit symlinks

This makes two changes:
1) it only tries to create the symlink if the bare .so doesn't exist
2) it looks for both a so.1 and a so.0 to link to .so
debian_installer: modify logind.conf to not handle lid events
debian_installer: update some comments
debian_installer: fix bugs in finalize.sh

- fix avahi-daemon install (mis-spelled package name)
- run apt-get autoremove after the updates and installs finish