v2.1 : update packages, paritions, remove user option

Platformio uses standard release packages and tools
No need for custom littlefs script
Remove pressure sensor noise variance user configuration (KF3 algorithm vestigial option for shaping overall response)
Reorder partitions, littlefs now has 190kBytes available

v2.0 KF3 KF4 options and test code

This is the last release containing a build option for the KF3 algorithm, and some test code to dump sensor noise statistics. Future releases will only use the KF4 algorithm.

Final esp-idf v3.x release

1. Build environment updated to ESP-IDF v3.3.5, Arduino-ESP32 v1.0.6, toolchain v1.22-0.97
2. New procedure for creating and flashing the SPIFFS partition image

Deprecated

With the changes in Arduino component for ESP-IDF and changes in ESP-IDF, it's become difficult to get a combination of the two that will work together without compile errors. For example, my version of the Arduino respository did not compile with ESP-IF v 3.2.2 for me. And since I didn't upload the Arduino component files here (too many), it would be difficult :-) for anyone downloading the code to make it even compile.

So I decided to just tag this version for archival

v0.9 onwards will have the required Arduino component files included in this repository and will be associated with a specific ESP-IDF release e.g. v3.2.2