todo list

- Reflect changes from src/error.cpp in libexiv2 to src/libpyexiv2.cpp: new error messages, error codes changed
- Add a 'doc' builder to the SConstruct to build the module's documentation
- Rewrite the exiv2 command-line tool and the test binaries in Python and (Python) scripts to run the same tests that are run to test exiv2
- Write a complete documentation for the binding and it uses
- Write unit tests (http://docs.python.org/lib/module-unittest.html)
- Use pkgconfig with scons in order to check the dependencies before compiling (http://www.scons.org/wiki/UsingPkgConfig)