Blender Git Loki

Speedup for ngon normal calculation

- BM_mesh_normals_update was looping over all faces to find the largest one, this is no longer needed.
- calculating a face normal was looping over every faces corners twice, now only once - using the loops directly (not an iterator).
- face vert locations were being copied an array, now use directly.
- calculating the normals would copy a float vector for the next point in the face, which was never used (only current and previous used).
- was copying vectors to compute the normal, now just assign the float pointers.