Update comments for serial port.

Add simulator over USB commands

Add websocket to drive api

Allow data augmentation on tub outside of training

Restrict support to python 3.6 and 3.7

* Add image augmentation as a standalone Tub member function which replaces the images in place.
* Refactor the augmentation to separate into conversion between numpy arrays and PIL images and the augmentation functions
* Add a donkey command 'donkey tubaugment' to augment tubs in place or clone the tub into a now one with augmentation and keep the original.
* Add a test that checks the augmented data only differs slightly from the original images

Linked with previous commit.

Easier to swap between.

Linked with #576 .   No automatic way at the moment for picking the serial port when using USB_SERIAL for simulator control.  This will have to do.

Mm1 Enhancement

Add inverted pwm drivetrain

Update train_autopilot.md rsync command

Vvong/fix duplicate jpg

tubplot option fix

Add back ImageListCamera support 

Add mock drive train for local development

Merge branch 'quick-fix-pygame-windows' of https://github.com/AchimTuran/donkeycar into AchimTuran-quick-fix-pygame-windows

removed incorrect hashes as per issue 23 in gym-donkeycar