2. Switch web controller to use the websocket api

Add support for MPU9250

Co-Authored-By: Michał Sochoń <kaszpir@gmail.com>

Co-Authored-By: Michał Sochoń <kaszpir@gmail.com>

Co-Authored-By: Michał Sochoń <kaszpir@gmail.com>

Co-Authored-By: Michał Sochoń <kaszpir@gmail.com>

Co-Authored-By: Michał Sochoń <kaszpir@gmail.com>

Co-Authored-By: Michał Sochoń <kaszpir@gmail.com>

Co-Authored-By: Michał Sochoń <kaszpir@gmail.com>

Update build_hardware.md

Update setup_jetson_nano.md

Support for Realsense D435 and D435i depth cameras

- change output type from depth_array to gray16_array, which allows us to use this output format for any 16bit grayscale image, not just depth array.  Based on pull request feedback from Rahul.

fix roll your own link

updated path for OpenCV module for Jetson Nano

Voice control update

2. fix line length, grammatic and formatting issues
3. Error handling if request failed
4. Fix README

Voice control by Alexa

Fix issues with xboxswapped controller

- added a comment to clarify what dependencies are necessary and how to install them.

- Changed to allows use default time for wait_for_frames()
- Those above changes were verified in realsense_viewer.py in the realsenseutils project to make the 3 streams stable and reliable on the jetson nano

- added traceback in Vehicle.py to print any exception that terminates the vehicle loop, other than a keyboard interupt.

- added traceback in Vehicle.py to print any exception that terminates the vehicle loop, other than a keyboard interupt.

- added exception handler in Vehicle.py to print any exception that terminates the vehicle loop, other than a keyboard interupt.

- modified complete.py/manage.py to save depth and 'depth_array' type, so it can be handled specially in datastore.py
- modified datastore.py to handle 'depth_array' as a 16bit grayscale PNG image.