appman-controller tool should cleanly cancel installation on termination (ctrl-c) and after timeout (say, around 5minutes).

This is a suggestion after talk with rgriebl, to ease development work on systems with primitive UIs.

When run without automatic acknowledge, appman-controller currently hangs indefinitely if UI does not react to installation acknowledge request. If terminated before acknowledge - it leads to inconsistent system state.

As currently nothing shows that installed package is unacknowledged, that leads to potential  problems with debugging.