Added nitpicky to sphinx and fixed warnings

bob/bio/base/algorithm/BIC.py

bob/bio/base/algorithm/__init__.py

bob/bio/base/database/__init__.py

bob/bio/base/database/database.py

bob/bio/base/database/file.py

bob/bio/base/extractor/__init__.py

bob/bio/base/preprocessor/__init__.py

doc/conf.py

doc/nitpick-exceptions.txt