Merge branch 'normalattrib-initialize-0' into 'master'

NormalAttrib: default props to 0 instead of undefined

See merge request !61
9 jobs for master in 4 minutes and 22 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #75779
VS2015
VS2015-32-bit

00:01:12

passed #75778
VS2015
VS2015-64-bit

00:01:23

passed #75777
VS2017
VS2017-32-bit

00:01:09

passed #75776
VS2015
VS2017-64-bit

00:01:17

passed #75773
Linux
clang-c++11

00:02:34

passed #75775
Linux
cppcheck

00:00:22

passed #75780
Linux
doc

00:00:17

passed #75772
Linux
gcc-c++11

00:02:11

passed #75774
Apple
macos-c++11

00:02:57