Have the survey pattern line end arc count change dynamically with line spacing.

[rolker]

From @valschmidt

"For a 40 m line spacing 6 points on the turn seems to be working pretty
well. But it occurs to me that with a wider line spacing one might want
more points. I realize I can adjust the manually, but we might consider
a rule of thumb that can be applied by default. I’m not sure what that
should be yet, but it might scale linearly."

[rolker]

This is no longer necessary as the boat now connects lines with Dubins curves.