Fix ImportError during selftest. Remove path silliness.

Also apply PEP8 and print Pillow version during test.
Tested on Windows with Python 2.6 to 3.3, 32 and 64 bit.
Without this patch, selftest.py would fail with an ImportError after `setup.py build_ext -i`:
```
Traceback (most recent call last):
  File "selftest.py", line 17, in <module>
    from PIL import Image
ImportError: No module named PIL
```