libtins-4.2-bp154.1.31

- Update to version 4.2
- build-patch adapted
  * add    libtins-4.2_build.patch: for new version
  * remove libtins-3.5_build.patch: now outdated
- use source download service

- Devel package must depend on libpcap-devel

- Ensure neutrality of description.

- Update to version 3.5 (see CHANGES.md)
- Refreshed libtins-3.2_build.patch as libtins-3.5_build.patch

- Initial release