Rudimentary file versioning.

Rudimentary file versioning.

Embed file version info in the resource file so that right-clicking the
executable shows the application version.

Unfortunately the version field must be formatted in a particular way so
we can't reuse the NSSM_VERSION #define from nssm.h but instead must
create a new #define and remember to update it when making a release.

Thanks fREW Schmidt.