Adapt to Swift 1.13.1

This reflects the recent changes in the swift codebase.
changed sample account
Merge branch 'for-icehouse' of github.com:morrisson/slogging into morrisson-for-icehouse
a few fixes to tests -- a lot more to be done
Usage info in JSON format

Before this commit, Slogging only outputs usage info in CSV file.
To enhance usability, the output format of choice is increased.