Add a note about [0, 0, 0] and cogl_vector3_normalize()
Add a note about [0, 0, 0] and cogl_vector3_normalize()

When having the [0, 0, 0] vector, normalize() won't try to divide by 0
and thus it's always safe to use that funtion.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 64370e7ddd32f25556a1792c00d14adc48a81d45)

Distrotech/cogl,Distrotech/cogl,Distrotech/cogl,Distrotech/cogl