Update setup_jetson_nano.md

* Use index to correctly go from first to last frame
* Use index from tub instead of try/catching on continuous frames
* Use picture frame size to determine mid of and length of user / pilot line plots
* Remove unused code/variables
* Some pep-8 formatting

Fix PartProfiler showing wrong number for KerasLinear

Fix PartProfiler to take KeyboardInterrupts into account as well as initialisations of parts. It seems like on_part_finished() is not called when a KeyboardInterrupt occurs leaving the time value in the time difference which messes up the timing table max and avg values. Here, we simply chop off first and last entry form the timing arrays. We also add a median to the table to see if the distribution of timings is skewed.

PS3 controller is not compatible with Jetson Nano

Update setup_jetson_nano.md docs with the correct unversioned directory names

Update supported_cars.md

At lines 103-104 the mv command removes the version IDs from the directory names for opencv and opencv_contrib.  This change makes the cmake command starting on line 123 consistent with these directory names.

Minor update to RotaryEncoder in encoder.py part (fix shutdown code)