Documenting and changing the documentation stuff

bob/learn/em/ML_gmm_trainer.cpp

bob/learn/em/__MAP_gmm_trainer__.py

bob/learn/em/__ML_gmm_trainer__.py

bob/learn/em/__empca_trainer__.py

bob/learn/em/__init__.py

bob/learn/em/__isv_trainer__.py

bob/learn/em/__ivector_trainer__.py

bob/learn/em/__jfa_trainer__.py

bob/learn/em/__kmeans_trainer__.py

bob/learn/em/__plda_trainer__.py

bob/learn/em/gmm_base_trainer.cpp

bob/learn/em/include/bob.learn.em/ISVTrainer.h

bob/learn/em/isv_trainer.cpp

bob/learn/em/ivector_trainer.cpp

bob/learn/em/jfa_trainer.cpp

bob/learn/em/kmeans_machine.cpp

bob/learn/em/kmeans_trainer.cpp

bob/learn/em/linear_scoring.cpp

bob/learn/em/main.cpp

bob/learn/em/main.h