Draw tangent vectors on winDoor planes
winDoorVectors being plotted
Positioning rafters next to winDoors

when walking half a winDoor length from center of winDoor along the
surface you get to a point in euclidian space which we name 'walk point'

we project this point onto the winDoor plane. Then we can tell how well
it approximates the azimuth tangent vector.

the walk point has a corresponding point in angle space.
surface.horizontalSurfaceProjection() can tell us the phi value of the
point in angle space. We need to know this angle to be able to position
rafters right next to the winDoor frame.

by refining the walking distance we can improve the projection precision
and thus improve the positioning of the rafters.

currently we can measure the error but not refine the projection.
also the code is a mess.
something weird
experiment
Merge branch 'winDoor_rafters'

Conflicts:
	js/cons/designs/WinDoorSet.js
iterative improvement walkingDistance works
walkingDistance approximation works awesome ... sometimes
Renamings finally finalized ... for now!

Both Rafter and test suite runs without errors