created parser and entropy modules
triangle module
created utils module, refactored cross_validation to new file, fixed other modules
Added __init__ to src/. Fully implement Forward to be able to work with as filter_items. Running times of Forward and NodeIterator now are the same
Cross validation using Forward
Added basic impl. for MovieLens parser. Added info in README about setting up env.py file for pointing to local data files not in git
Merge branch 'master' into refactor