Scene floor not getting added correctly in ElevationHandler._cutaway. Adjust how inside was getting counted when starting in a hole.

When moving token into and out of hole in one movement, the elevation drops to large negative and then back.

The scene floor polygon was not getting constructed correctly for that situation.

Caused by two issues:
1. Steps not always capturing the start and end elevations correctly in the cutaway.
2. Duplicate points in the cutaway polygon screwing up the walk algorithm.

Change to use ramping straight lines from smaller to larger. Not perfect, b/c the stripes are still weird in some instances. But better.

Cannot set elevation using region segment movement, b/c the token elevation is already set by then. Instead, catch it in preUpdateToken hook. Somewhat undefined if multiple regions cover the area in which is teleported.