[refactoring2016] Moved bob.bio.db.BioDatabase to bob.bio.base

bob/bio/base/__init__.py

bob/bio/base/database/__init__.py

bob/bio/base/database/database.py

bob/bio/base/database/file.py

bob/bio/base/preprocessor/Filename.py

bob/bio/base/test/dummy/database.py

bob/bio/base/test/dummy/fileset.py

bob/bio/base/tools/command_line.py

requirements.txt