Added Pearson's correlation coefficient similarity
Merge branch 'master' of https://github.com/ntnu-smartmedia/elephant

# By Dag Einar Monsen
# Via Dag Einar Monsen
* 'master' of https://github.com/ntnu-smartmedia/elephant:
  Add build status graphic to README.
  Fix test file and add config for travis CI.
  Use full data set instead of sample.
  Remove print statements and fix indentation.
  Update README.
  Create test for User.get_rating_average().

Conflicts:
	src/SimpleKNN.py