A bug

1.without "float" in coefList.append(float(coef))
there is an error "typeError: cannot perform reduce with flexible type"
new function

new function:
1.store the result in "coef_result.txt"
in the txt, the coef for LR is stored. Besides, the timeInterval, the
positive sample and the negative sample size are also recorded
2.select the business reviewed by more than 1000 users
shuflle_test

new function:
1.shuffle the reviewing time, verify the social influence
2.select the business reviewed by more than 10 users in the period
delete_reviewHistogram

change this file name