fixing field setters and type constructors (issue #24)
fixing field setters and type constructors (issue #24)

norton/chibi-scheme,holmescn/chibi-scheme,holmescn/chibi-scheme,norton/chibi-scheme,norton/chibi-scheme,norton/chibi-scheme,norton/chibi-scheme,holmescn/chibi-scheme,holmescn/chibi-scheme,norton/chibi-scheme,holmescn/chibi-scheme