Add a pkg-config control file

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Makefile.am: Correctly install all the headers

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
README: Update the example, and add compile instructions

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