Update SummaryGenerator module; fix library dependencies (NuGet)

- Update SummaryGeneratorTest.
- Adjust SummaryGeneratorTest code so that it works with recent changes to
  SearchSummary module.
- Add SummaryGeneratorFactory.
- Update ISummaryGenerator interface.
- Add fileReader field to MatchingFile struct.
- Fix external library references.
- Add libraries to multiple projects via NuGet.