Added week6

cp/tests/__init__.py

cp/tests/tests_week06.py

cp/tests/unitgrade_data/Week06ExtractKeywords.pkl

cp/tests/unitgrade_data/Week06GetPeopleByLanguage.pkl

cp/tests/unitgrade_data/Week06LetterHistogram.pkl

cp/tests/unitgrade_data/Week06MultiTap.pkl

cp/tests/unitgrade_data/Week06SentimentAnalysis.pkl

cp/tests/unitgrade_data/Week06SpellCheck.pkl

cp/tests/unitgrade_data/Week06TextToNato.pkl

cp/tests/unitgrade_data/Week06TruncateAndNormalize.pkl

cp/tests/unitgrade_data/Week06WordHistogram.pkl

cp/utils/__init__.py