make --version to report the binary version again

[dopstar]

Fixes #57

[homotechsual]

Would be great to see this merged and ideally for the binary to actually use the Version property on Windows and others where supported.

C:\RMM\Bin> (Get-Command 'C:\RMM\Bin\librespeed-cli.exe').Version

Major Minor Build Revision

---

0 0 0 0