[PDI-9206] Ability for the MongoDB output step to be able to convert and insert a JSON string into MongoDB.
[PDI-9206] Ability for the MongoDB output step to be able to convert and insert a JSON string into MongoDB. Unit tests for new functionality.
Removed an unused member variable.
Merge pull request #88 from m-a-hall/mongoInOutImprovements

[PDI-9206] Ability for the MongoDB output step to be able to convert and insert a JSON string into MongoDB.