Small adjustments

Move entropy.py -> __main__.py so that it can just
be used by running $ python entropy (inside the
entropy root folder).

Also use yaml loading instead of json loading since
yaml allows for comments inside the file (yaml is
a superset of json).

Removed import json from __main__.py to keep pep8 happy

Also changed react.py to use a per module logger instead
of root logger

Change-Id: I5eb24319dee4f04891878c6e61cc4d7835b14d34