Renaming variables - *_arohner.py version

Changed variable names

w8_3d = weight_3d

a_fld = a_3d

b_fld = b_3d

g_fld = growth_rates

(?) wfld = weight_3d (?)

tc_fld = input_temp_3d

yy = every_year

life_cycle = generation

Note: Did not rename wfld to be identical with w8_3d so far to weight_3d.

-> Is w8_3d identical with w_fld?