msi versioning

[tlecomte]

The automated versioning currently takes major and minor from the git tag, but leaves build and patch unset.

This causes issues when testing the msi installers, because the version need to be different, otherwise the MajorUpgrade feature fails, leaves duplicate entries in the configuration panel, also fails to remove previous files.

So we should generate build and patch if possible (or use the commit sha to differentiate versions), so that each msi installer has a unique version.