* integration test changes to override heatup to 1000 steps + run each preset for 30 sec (to make sure we reach the train part)
* fixes to failing presets uncovered with this change + changes in the golden testing to properly test BatchRL
* fix for rainbow dqn
* fix to gym_environment (due to a change in Gym 0.12.1) + fix for rainbow DQN + some bug-fix in utils.squeeze_list
* fix for NEC agent
allowing for the last training batch drawn to be smaller than batch_size + adding support for more agents in BatchRL by adding softmax with temperature to the corresponding heads + adding a CartPole_QR_DQN preset with a golden test + cleanups
* updating the documentation website
* adding the built docs
* update of api docstrings across coach and tutorials 0-2
* added some missing api documentation
* New Sphinx based documentation