added post processing steps for I-Vector (sequential and parallel)

bob/bio/gmm/algorithm/IVector.py

bob/bio/gmm/config/algorithm/ivector_cosine.py

bob/bio/gmm/config/algorithm/ivector_lda_wccn_plda.py

bob/bio/gmm/script/verify_ivector.py

bob/bio/gmm/test/data/scores-nonorm-ivector-cosine-dev

bob/bio/gmm/test/data/scores-ztnorm-ivector-cosine-dev

bob/bio/gmm/tools/command_line.py

bob/bio/gmm/tools/ivector.py

setup.py