Chessanalytics

Decided to combine chessanalytics and chesssanalytics-st libraries into one, make it more functional and user friendly.
I am planning to restructure the lib a little bit in the future on users favor - make it something like CA.stats.pearson() or CAST.moves.king_moves(), but that are long term plans :)

decided to add detailed output for get_all function. in previous situations outputs generated sometimes were certainly not clear, had different lengths and it was hard to see which parameters are lacking. Now, when its returned as a dict of dicts, you can clearly see which parameters are absent, what is what etc.

updated functionality and fixed README.md (again).

added functions squares_with_promotions, squares_with_checks, squares_with_mates

fixed some typos in README.md, made it look better