zooplankton cumulative diagnostics

[cayelan]

Looks like currently only last Z group gets their process values into the diagnostics

libaed-water/src/aed_zooplankton.F90

Line 708 in 1e20f9e

_DIAG_VAR_(data%id_grz ) = zoo*grazing*secs_per_day

Should be updated to cumulate over species, or one set for each