Resolve "Version in pet-File not always MAJOR.MINOR.PATCH"
We have projects where the version is not MAJOR.MINOR.PATH but rather only MAJOR.MINOR
See e.g. Z:\experiments\2020.06.16_Juelich_IEK6H3_Engstelle\export\simplylife with version 0.8
Solution:
- Treat all old versions without patch as the same version, i.e. patch = 0 (results in pessimistic comparison; without patch never newer than version with same major.minor)
- Add Unit-Test to ensure Major.Minor.Patch from now on
Closes #321 (closed)