debian: Adjust the VCS-Git header

The VCS-Git URL should also contain the branch the packaging is on, so
add it, as it is not the default branch.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
debian: Move the API docs from the library to the -dev package

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
debian: Add a git-buildpackage config file

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