Use AM_INIT_AUTOMAKE to set the foreign option

Instead of having AUTOMAKE_OPTIONS=foreign in every Makefile.am, put
it in configure.ac instead.

While there, also enable support for silent rules (off by default).

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Update the travis build script

The install stage should apt-get update too, and do both that and
install quietly. Also, while there, configure with silent rules
enabled: we don't set any special compiler flags, there's no need to
see the exact commands in the CI.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>