Looked into the failed testcases

I've just looked into the failed testcases these days. Reasons of the failures can be fallen into below several categories:

• PyInstance_NewRaw: should find a replacement
• A lot of things related to the Unicode string changes
• IO module changed (see PEP 3116), some PyFile_* dissappeared
  
• How to define swig::LANGUAGE_OBJ?
• Some old testcases code should be rewritten (eg. they should raises an exception object instead of a string)
• Exception implementation: in Python 3 all excetion classes must inherit from BaseException, so we can't directly use a C/C++ struct as an exception now.

This would be a todo-list for me in the next weeks.