Refactor: Correct comment.
Class must include Packable/Unpackable even if parent class including Packable/Unpackable.
Add format not modifiable test case.
Added "define_strcut" class-macro.
Refactor: Remove checkvardef method.
Support pointer.
Support struct array.
Support nested struct.
Support unpackable struct.
Refactor: Method internal_format to be protected.
Abstracting  Field-accessor by proc-object.
(for support hash-style [:sym] access)
Refactor: Remove unused instance methods.
Refactor: Move methods Base::ClassMethods to Unpackable::ClassMethods.
Documentation: Use README.doc as index.html.
Update VERSION constant change to 0.0.3.
Update gemspecs for v0.0.3 release.