Allow 2d outputs to be obtained via GET
Allow 2d outputs to be obtained via GET

This also recognizes that cjson is not required for 2d
outputs, but it is required for 3d outputs.

Signed-off-by: Patrick Avery <743342299f279e7a8c3ff5eb40671fce3e95f13a@kitware.com>

OpenChemistry/mongochemserver