Remove occlusion ellipses and extended tick mark rays.

Stop drawing extended tick lines for debugging now that the clock layout
is consistent. Previously, all major and minor tick lines were drawn
from the center of the clock to the perimeter, creating a helpful moire
pattern in which any layout inconsistencies were easy to discern
visually. A white occlusion ellipse would be drawn over the center of
the clock to hide the patterns, yielding the visible set of tick marks.
Neither of these techniques is necessary now. Draw and transform only
the visible portion of the tick mark and no occlusion ellipse is
necessary.