Add convenience methods for checking whether an ExecRes failed or succeeded. Split up GitWrapper#failed.

core.quotePath and core.precomposeUnicode should remove unicode related problems caused by having to unquote paths

return an Optional<List> from getMergeCommits() as an empty Optional indicates failure whereas an empty List indicates absence of merge commits, store SUMMARY and BOUNDARY header fields in the 'other' Map

Return the actual name of the commit from its getId() function, this way Repository#checkout(Reference) will bring one 'on the branch' if the given Reference is a Branch.

differentiate between failure modes in the logging done in importRepository(), try and use the canonical file path for the URL as a fallback