Updated binary release

This release contains a binary version of the Vale tool that supports building https://github.com/project-everest/hacl-star/tree/master/vale . The binaries are .NET executable and dll files, which run on Unix with mono ( https://www.mono-project.com/ , see https://github.com/project-everest/vale/blob/master/INSTALL.md ) or on Windows. The tool implements Vale for Dafny and F*.

Version 0.3.15 upgrades to an upcoming F* release.