REALISING

Add a release note to NEWS.md.

Set 2GEOM_MAJOR_VERSION, 2GEOM_MINOR_VERSION, and 2GEOM_PATCH_VERSION in CMakeLists.txt.

cmake .
make
make test
make dist

Next, copy lib2geom-${VERSION}.tar.bz2 to `/tmp/``, extract it, and verify it builds.

gpg --armor --detach-sign --output lib2geom-${VERSION}.tar.bz2.sig lib2geom-${VERSION}.tar.bz2
git tag -s ${MAJOR}.${MINOR}
git push --tags