Task list for 1.0

[DougLau]

• Default values
  • Deserialize with #[serde(default = "path")] attributes
  • Deserialize from schema
  • Omit values equal to default when serializing
• Schema
  • Deserialize separate
  • Serialize prepended
  • Serialize separate
  • Value enum without #[derive(Deserialize)]
  • Serialize from Value enum
• Builder for Serializer -- pretty printing options