Add a note about how TA-Lib handles NaN's. 

update changelog 

remove pyproject.toml which may be preventing some installs. 

Regenerate _ta_lib.c. 

Fixed{MIN/MAX/MINMAX}INDEX functions to return correct indices. 

Update to 0.4.20. 

README: formatting. 

Update changelog 

README.md: minor clarification. 

update changelog.