Introduce keep_empty_properties_by_default option to force display of editors even for empty properties.
Merge branch 'feature/keep-empty-properties' of https://github.com/blabno/json-editor

* 'feature/keep-empty-properties' of https://github.com/blabno/json-editor:
  Introduce keep_empty_properties_by_default option to force display of editors even for empty properties.