fix for lines that are exactly horizontal or vert plus cleanup

Change-Id: I4ed601dd5ea9c916ad0feb81b6399c222d68812e
fix for lines that are exactly horizontal or vert plus cleanup

Change-Id: I645fe0f1a9c348f61044171c85781b626173c5a5
add support for cell normals

Change-Id: I6e59e009962a39fd04d71fc096a23a2d74b3aa3a
add support for cell normals

Change-Id: I646b4180290cf14b99dd366680c2e3dc65862d78
Merge topic 'line_lighting_fix' into master

4b933627 fix for lines that are exactly horizontal or vert plus cleanup
a9007307 fix for lines that are exactly horizontal or vert plus cleanup
Merge topic 'the_cake_is_a_lie' into master

b53b163d add support for cell normals
51b0de48 add support for cell normals