Extracted super class AbstractTest for all junit tests which sets up the objectmapper.
Added AMSSerializationModule which sets upp mixins.
Added SearchItemMixIn which sets the @JsonProperty used by the AMS API.
Updated AbstractTest to set up objectmapper with AMSSerializationModule.
Updated AMSApiClient to set up objectMapper with AMSSerializationModule.
removed unwrap root value feature for object mapper since it should only be used with list objects.
Added new abstract test class for list tests which sets the unwrap_root_value feature.
List tests should extend the AbstractListTest so the objectmapper is set up properly.
Added mixin for Ad to separate AMS specific field names from the Ad class.
removed om field since it was hiding the one from AbstractTest.
Moved AMS Specif Json field name declarations to MixIn
Bumped version