TODO codes
 function returning maximum depth of mixed layer.
 function based on  where they use a threshold density difference of .03 kg/m^3
mixing layer depth, with (de Boyer et al., 2004) method and zuml for Souther Ocean (Mitchel & Holm-Hansen, 1991)
update version and new functions
add Contributor
Merge pull request #2 from arnaldorusso/kduml

Kd(PAR) and ZUML functions