contrib: add script for triggering a openSUSE Build Service build
spec: use constant filename for source tarball

This avoids filling up the OSB repo with new files for every build.
spec: add timestamp and Git hash to Release field

This allow us to build nightly packages that will be correctly
upgraded.
spec: remove malformed changelog entry
spec: avoid hard-coded paths

This triggered the following rpmlint error:

  E: hardcoded-library-path in /usr/lib/libvalidator.so*
spec: add missing BuildRequires
Makefile: install libraries /usr/lib64 on x86_64

When building on a 64-bit machine, we'll expect to find the libraries
in /usr/lib64.
spec: run ldconfig when installing/uninstalling