Added generating of new version for each DX Compiler build.
There are 3 kinds of version:
1. **Official build**
Built by using `hctbuild -official`. The version is based on the current DXIL version, latest official release and a number of commits since then. The format is `dxil_major.dxil_minor.release_no.commit_count`. For example a current official version would be something like `1.5.1905.42`. The latest release information is read from `utils\version\latest-release.json`. The `1905` corresponds to `dxil-2019-05-16` release branch and `42` is the number of commits since that release branch was created. For master branch the `commit_count` will be incremented by 10000 to distinguish it from stabilized official release branch builds. So the current official version of master would be someting like `1.5.1905.10042`.
2. **Dev build**
Build by using `hctbuild` with no other version-related option. The format is `dxil_major.dxil_minor.0.commit_count` where commit_count is the number of total commits since the beginning of the project.
3. **Fixed version build**
Build by using `hctbuild -fv`. Enables overriding of the version information. The fixed version is read from `utils\version\version.inc`. Location of the version file can be overriden by `-fvloc` option on `hctbuild`.
In addition to the numbered version the product version string on the binaries will also include branch name and last commit sha - `"1.5.1905.10042 (master, 47e31c8a)"`. This product version string is included in `dxc -?` output.
Helena Kotas
Marcelo Lopez Ruiz