Added tons of documentation

bob/bio/base/algorithm/Algorithm.py

bob/bio/base/algorithm/BIC.py

bob/bio/base/algorithm/LDA.py

bob/bio/base/algorithm/PCA.py

bob/bio/base/algorithm/PLDA.py

bob/bio/base/config/grid/local.py

bob/bio/base/database/Database.py

bob/bio/base/database/DatabaseBob.py

bob/bio/base/database/DatabaseFileList.py

bob/bio/base/extractor/Extractor.py

bob/bio/base/extractor/Linearize.py

bob/bio/base/grid.py

bob/bio/base/preprocessor/Preprocessor.py

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

bob/bio/base/test/test_databases.py

bob/bio/base/test/test_scripts.py

bob/bio/base/tools/FileSelector.py

doc/conf.py

doc/implementation.rst

doc/implemented.rst