Converts a org.json4s.ast.fast.JValue to a org.json4s.ast.safe.JValue.
Converts a org.json4s.ast.fast.JValue to a org.json4s.ast.safe.JValue. Note that when converting org.json4s.ast.fast.JString, this can throw runtime error if the underlying string representation is not a correct number. Also when converting a org.json4s.ast.fast.JObject to a org.json4s.ast.safe.JObject, its possible to lose data if you have duplicate keys. Duplicate keys are not allowed in JSON as per RFC-4627
Implements named extractors so we can avoid boxing