added link to naive bayes
drop old R exercise
start to introduce new exercise
add more activity steps
move nltk stemming to 11-NB; closes #177
move salary.R; closes #191
add ISL reading to 10; closes #26
add  hint
put link to types of NB back in
update homework
Merge pull request #197 from ajschumacher/update_nb

update naive bayes class and close some issues
better wording
add CountVectorizer link
add better logistic assignment language
Merge pull request #198 from ajschumacher/finish_week

a little more for 11 and 12
added scrapers made in class
Merge branch 'master' of https://github.com/ajschumacher/gadsdc
fix markdown link
remove spaces from filename
Merge pull request #200 from justmarkham/fixes

remove spaces from filename