v2.0

• Major changes:
  • GHC 7.8 support (see #49);
  • Switch to classy field lenses (see #41);
  • Add Data.Swagger.Schema.Validation (see #18);
  • Add Data.Swagger.Operation with helpers (see #50);
  • Add IsString instances for some types (see #47);
  • Add helpers to sketch Schema from JSON (see #48).
• Minor changes:
  • Make NamedSchema a data rather than type (see #42);
  • Change Definitions to Definitions Schema;
  • Add schema templates for "binary", "byte" and "password" formats (see 63ed597);
  • Add Monoid instance for Contact;
  • Change tags to be Set rather than list.
• Fixes:
  • Fix schema for () and nullary constructors (see ab65c4a);
  • Fix Operation FromJSON instance to allow missing tags and parameters properties.