Fix pline intersect function to use pos_equal_eps

[hhemul]

In case of segments not intersecting but close enough (in pos_equal_eps box) there will be incorrect behavior. If bound boxes isn't overlap but segments intrsects.
For examle: 2 perpendicular segments
*
|
|
*
-------
with distance between less than pos_equal_eps but greter than T::epsilon()
In that case should be intersection but it won't

[jbuckmccready]

Thanks for the pull request! Good catch, the "fuzz" variable was old code that I missed updating.

Can you add a unit test case which fails before the change and passes after the change in the test module at the bottom of the file?

I think it should be easy to trigger with two perpendicular lines as polylines similar to the ascii picture you made.