Sometimes the lowest threshold is missing

[mbostock]

E.g., if the domain is

[-149.76192742819748, 321.19300631539585]

and 14 ticks are desired, then the estimated tick step is 50

tickStep(-149.76192742819748, 321.19300631539585, 14)

and hence the resulting “niced” domain is

[-150, 250]

which when passed to ticks as

ticks(-150, 250, 14)

produces

[-140, -120, -100, -80, -60, -40, -20, 0, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240]

and notice that –140 is greater than the original minimum. Related d3/d3-scale#209

We should be using d3.nice instead. d3/d3-array#174

ticks(...nice(-149.76192742819748, 321.19300631539585, 14), 14)

which produces

[-150, -100, -50, 0, 50, 100, 150, 200, 250, 300, 350]

although we should drop any threshold greater than or equal to the maximum.