TensorFlow Lattice 2.0.4

Changes:

• Save/load support for Keras models (HDF5/H5 format)
• RTL layer: An ensemble of Lattice layers that takes in a collection of monotonic and unconstrained features and randomly arranges them into lattices of a given rank.
• AggregateFunction Premade model and Aggregation layer: Applies monotonic function on set inputs passed in as ragged tensors.
• Crystals Lattice ensemble with Premade model
• Feature updates to Lattice layer
• Updates to tutorials
• Bug fixes

PyPI release:

• Generic package for py2/py3 that should work for TF 1.15 or TF 2.x.