Fixed merge conflicts, filter out empty values

[AndreiVidrasco]

JSON Output with initial implementation included all default values, like empty dictionaries or empty arrays. Because of that output json was quite big. If we filter out those resulting json becomes much smaller, in my case it was 90% size reduction.

[ryohey]

@AndreiVidrasco Thank you for your pull-request! We decide to do not remove empty dictionaries or empty arrays in toJSONValue() because it is useful in some situation and to remove complexity. It is discussed at yonaskolb#545 (comment).

All these if array.count > 0 { are not really required. It might be useful for some use cases to generate out all the empty arrays. For the compact spec you have now, there could be a function JSONDictionary.removeEmptyArrays that loops through and removes all empty arrays
yonaskolb#545 (comment)

Definitely your suggested feature is needed to generate human readable JSON. I considering it to filtering empty values within whole JSON recursively after ProjectSpec.toJSONDictionary() instead of processing in each toJSONValue().
I suggest that you make a pull-request that adding the feature that filters our empty values to yonaskolb's repository after yonaskolb#545 is merged.

[AndreiVidrasco]

Ok, thanks. I will follow your pull request to and submit a new one to yonaskolb later