Added collaborative filtering features to clu_overall algorithm
Added load_csv_file method to ETLUtils class
Created a new method to export a list of dictionaries into a csv file
Modified the extractor module so it can handle ranges as a parameter when initializing the users (when clusters are used). Also dropped the ratings field in the reviews dictionary as it was not necessary
Created a module where an external recommender system (oscar celma python-recsys) is tested in order to have a benchmark
Modified the recommender systems so that the similarity metric can be passed as a parameter