remove duplicated outputs

[plight-cmu]

Remove the duplicate printing of level 2, as well as duplicated optional fields.

Problem:
  1. When running part_3_convert_json.py, we saw that the contents of level 2 are printed out twice, instead of seeing level 1 and level 2 in order.
  2. Also, optional fields are printed twice in the second repetition of the field

Solution:
  In each iteration of the loop, create new objects for the level and fields read in. The
  duplication was caused by adding the exact same object to the level pack twice.