Final version of take 4

Same functionality of take 4 but with
tidy up code.

Margins table with changing depth (fm0 not improving, fm1 improving):

d: 0, fm0: 3, fm1: 3
d: 1, fm0: 4, fm1: 4
d: 2, fm0: 6, fm1: 6
d: 3, fm0: 7, fm1: 10
d: 4, fm0: 11, fm1: 15
d: 5, fm0: 15, fm1: 21
d: 6, fm0: 21, fm1: 29
d: 7, fm0: 27, fm1: 37
d: 8, fm0: 35, fm1: 47
d: 9, fm0: 42, fm1: 57
d: 10, fm0: 51, fm1: 68
d: 11, fm0: 60, fm1: 81
d: 12, fm0: 70, fm1: 94
d: 13, fm0: 81, fm1: 108
d: 14, fm0: 92, fm1: 123
d: 15, fm0: 104, fm1: 139

bench: 4364793