Zhang 2017 is not a chronological clock

[karoliskoncevicius]

In the current README Zhang 2017 is listed as chronological clock: https://github.com/MorganLevineLab/methylCIPHER#chronological-age-predictors-1.

However, it calculates all-cause mortality risk score and should probably be among biological and mortality clocks: https://github.com/MorganLevineLab/methylCIPHER#biological-age-and-mortality-predictors-1

[karoliskoncevicius]

On the same note - why is Horvath's Skin and Blood clock included under non-blood clocks?