* Fixes internal brain for Banana Imitation.
* Fixes Discrete Control training for Imitation Learning.
* Fixes Visual Observations in internal brain with non-square inputs.
* Revamps agent code for walker and crawler environments to use shared JointDriveController system.
* Crawler has been reworked to be very cute.
* Crawler & Walker environments have been reworked to be visually consistent.
* Added Dynamic Crawler scene.
* All scenes re-trained and new models added.
* Documentation changes.
Updates to CameraSensor / CameraSensorComponent:
* new settings object to set up layer masks, depth, etc
* support for arbitrary # channels returned by the sensor
* channels include depth, layer mask, RGB, or grayscale
Updates to VisualFoodCollector:
* food doesn't roll (for now), simplifies learning without stacking
* added layers
Updates to mlagents_envs:
* decode multiple pngs packed into a single observation