Elastic Horovod, Ray integration, CMake build, all-to-all op, gradien…

…t predivide factor

Hotfix to add PYTHONPATH to mpirun env

Hotfix for sync batch norm in PyTorch 1.5, mixed precision in TensorF…

…low 2.2

Hotfix for horovodrun network interface discovery process

LSF support, Spark on Gloo, bugfixes and performance improvements

TensorFlow 2.2 compatibility, framework install deps, MPI args for ho…

…rovodrun, bugfixes

Horovod Spark Estimators, Spark 3 support, Join operation, and Intera…

…ctive Run mode for notebooks

Bugfixes for MPI, Gloo, and TF Keras

Bugfix: autotune works with horovodrun, added log level arguments to …

…horovodrun

Horovodrun config file, TF: switch allreduce back to compute_gradient…

…s(), bugfixes