Added script for Day 6.
Merge pull request #14 from ramon-astudillo/master

Small clean-up in sequences
ENH Use sparse matrices for communication
ENH Load previous iteration results
MIN Remove unnecessary variables
BUG Use the whole dataset to build the dicts
Fixed the Big Data EM day.
merged with whatever was in the repository
merged with whatever was in the repository (take #2)
inserted print confusion matrix fig 2.4
Undo of pythonification in day 2.
Merge pull request #15 from zmarinho/master

day 2 print transition matrix
Removed unnecessary prints from exercise 2.9