Do not set properties not found in the dictionary.

In our application we had an entity which in some cases the JSON dictionary given by the server was missing some values. If a key in the dictionary is not found it shouldn't be setting the value of the entity.

Example:

Entity with nofitications_number property mapped to a value with the same key name in the dictionary, with an IntegerTransformer associated.
First JSON includes a notifications_number: 2
Entity.notifications_number = 2
Second JSON doesn't include a notifications_number and [dictionary valueForKeyPath:sourcePath] returns nil.
Entity.notifications_number = 0
When it doesn't make sense to translate a not found value.

Keep up the good work!