Consolidate lucid, maverick, natty, and oneiric templates into one 'ubuntu'
template.

Add support for specifying architecture.

Add support for '--trim|-x' option, which removes services like the lucid
template used to.  This creates smaller, faster-booting containers, but they
will not be safe with certain upgrades, like mountall or udev.  When -x is
not specified for lucid or maverick container, then install lxcguest from
the ubuntu-virt ppa, since it does not exist in the official archives, and
the container is not safe to boot without lxcguest.

Add support for '--bindhome <user>' option, which will cause /home/<user>
to be bind-mounted into the container, and create the user with his
original password, shell, and group memberships in the container.

changelog:
  june 23:
    lxc-ubuntu template: set lxc.arch in config
    install lxcguest when NOT trimming the container
    lxc-ubuntu: always install lxcguest in postprocess
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>