* 1st Round update for Python 3.7, TF1.15, Keras2.3
Move Tensorflow logging verbosity prior to first tensorflow import
Keras Optimizers and nn_block update
lib.logger - Change tf deprecation messages from WARNING to DEBUG
Raise Tensorflow Max version check to 1.15
Update requirements and conda check for python 3.7+
Update install scripts, travis and documentation to Python 3.7
* Revert Keras to 2.2.4