start developing new function tp
tf function beta has been finished.
Update tf(), idf(), tfidf()
Rename scripts/ to tools/. Add file tools/__init__.py
Add test data and tools module

add test data and tools module
add output function to tp.py
Add README.md
Modified README.md
Modified README.md. Add stopwords.txt
add setStopwdList function
adjust some comment
Modified some comment...
Add stemmer function
Ignore all .swp file
Add demo.py. Correct some function name
Adjust mechanism behind stopword filter
Refresh local files with files on working server