check-code: check for tuple parameter unpacking (missing in py3k)

removed exception args indexing (not supported by py3k) Py3k removed __getitem__ for exception classes. The correct way of getting the exception arguments is by using the args method.

util: use fakebuffer as buffer in py3k There's no buffer type in py3k, util.py has a function, called fakebuffer, that implements a similar API. This patch implements fakebuffer as a memoryview wrapper in py3k.