[release] Boost 1.78.0

Release 1.78.0 of the Boost C++ Libraries is now available.

These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use.

This release contains numerous enhancements and bug fixes for existing libraries.

For details, including download links, see <http://www.boost.org/users/news/version_1.78.0>

You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.78.0/>

To install this release on your system, see <http://www.boost.org/doc/libs/release/more/getting_started/index.html>

Thanks to everyone who participated in this release.

Thanks,

-- The Boost Release Team

Marshall Clow, Michael Caisse, Glen Fernandes