Use libspatialjoin for geometric relations, drop Boost dependency

[patrickbr]

This PR uses libspatialjoin to compute the geometric relations. It also completely drops the Boost dependency from osm2rdf (osmium still requires boost) by replacing all geometric stuff with its functional equivalent from util. Additionally, the Bzip2-zipping is now done manually (it was done via boost filtered streams previously).

Everything compiles and seems to work. The E2E tests are still failing, mainly because the mechanism to capture writes to stdout does not work anymore.

It would be great if anyone could test this and give some feedback.