Add the filelist interface

bob/bio/base/test/data/example_fielist/norm/train_world.lst

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

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

bob/bio/base/test/test_database_implementations.py

bob/bio/base/test/test_filelist.py

bob/bio/base/test/test_scripts.py

doc/filelist-guide.rst

doc/implementation.rst

doc/index.rst

setup.py