simple scan does not build on ubuntu 12.04 lts

when running make it fails with the error message quoted below.
we should discuss if it is desirable to always use the latest&greatest technologies if this means breaking backward compatibility.
at the very least we should offer a branch (in the git sense of the word, i don't know how bzr calls it) that works on some "baseline" distribution, and I strongly suggest to use the current Ubuntu LTS release as baseline.
it should not be necessary to run an unreleased development version of Ubuntu to get involved into Simple Scan development.

Below is the current make error message, probably introduced in the following commit:
http://bazaar.launchpad.net/~simple-scan-team/simple-scan/trunk/revision/581

nailor@needle:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.04 LTS
Release: 12.04
Codename: precise

nailor@needle:~/simple-scan$ make
make all-recursive
make[1]: Entering directory `/srv/datadisk/home/nailor/simple-scan'
Making all in src
make[2]: Entering directory `/srv/datadisk/home/nailor/simple-scan/src'
  VALAC simple_scan_vala.stamp
book-view.vala:71.65-71.68: warning: Argument 2: Cannot pass null to non-null parameter type
        scroll = new Gtk.Scrollbar (Gtk.Orientation.HORIZONTAL, null);
                                                                ^^^^
ui.vala:1267.19-1267.41: error: The name `get_default' does not exist in the context of `GLib.Application'
        var app = Application.get_default () as Gtk.Application;
                  ^^^^^^^^^^^^^^^^^^^^^^^
ui.vala:1267.13-1267.63: error: var declaration not allowed with non-typed initializer
        var app = Application.get_default () as Gtk.Application;
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ui.vala:1268.9-1268.11: error: The name `app' does not exist in the context of `UserInterface.load'
        app.add_window (window);
        ^^^
simple-scan.vala:88.9-88.21: error: The name `shutdown' does not exist in the context of `Gtk.Application'
        base.shutdown ();
        ^^^^^^^^^^^^^
simple-scan.vala:86.5-86.33: error: SimpleScan.shutdown: no suitable method found to override
    public override void shutdown ()
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Compilation failed: 5 error(s), 1 warning(s)
make[2]: *** [simple_scan_vala.stamp] Error 1
make[2]: Leaving directory `/srv/datadisk/home/nailor/simple-scan/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/srv/datadisk/home/nailor/simple-scan'
make: *** [all] Error 2