pylint 1.0 import names: logilab.astng ==> astroid

Prefer the new name, fall back to the old name.
Update to run with Python 3.3

2to3: print x ==> print(x)
string.letters() ==> string.ascii_letters()
type "unicode" no longer exists.
add Python 3.3 to setup.py list.
Merge pull request #2 from ziggr/master

Update to pylint 1.0 and python 3.3