Address unicode issues in database

When working with the database there are sometimes explicit representations of unicode characters (eg, \u2212) instead of what they should be (-). We need to investigate where this is happening; it is possible the input data is wrong (and thus a matter for the SIMPLE scripts) but we can probably force an encoding on the output JSON to ensure it doesn't happen on the file representation. The problem with having a mix of unicode characters is searching exact values can be much harder.