[sphinx] Fixed warnings

bob/bio/base/__init__.py

bob/bio/base/database/__init__.py

bob/bio/base/database/csv_dataset.py

bob/bio/base/database/file.py

bob/bio/base/pipelines/__init__.py

bob/bio/base/pipelines/vanilla_biometrics/__init__.py

...base/pipelines/vanilla_biometrics/biometric_algorithms.py

bob/bio/base/pipelines/vanilla_biometrics/legacy.py

bob/bio/base/pipelines/vanilla_biometrics/pipelines.py

...o/base/pipelines/vanilla_biometrics/vanilla_biometrics.py

bob/bio/base/pipelines/vanilla_biometrics/wrappers.py

bob/bio/base/pipelines/vanilla_biometrics/zt_norm.py

bob/bio/base/test/test_filelist.py

doc/extra-intersphinx.txt

doc/index.rst

doc/py_api.rst