[PDI-10209] MongoDB output step cannot insert an incoming field specified as "JSON" unless it is set as the value of a field in a top-level record; [PDI-10371] Data Integration - Kettle PDI-10371
Leaving "Write concern (w option)" blank should default to write concern 1, but actually defaults to 0. Also snuck in a small logging level change for messages relating to batch commits.
Merge pull request #30 from m-a-hall/json-top-level-insert

[PDI-10209] MongoDB output step cannot insert an incoming field specifie...