v0.7.0

Added

• only: [] and except: [] options that allow to controll what attributes are rendered/parsed
• render_nil: true option that allows to render nil values
• Allow to pass a context object to extractor/generator methods

Changed

• Pass whole document to methods for JSON/YAML/TOML so its behavior is consistent with XML mapping
• Convert splat arguments to keyword arguments
• RSpec: enable random spec execution and warnings