Merge branch 'halfedge-vector-and-length' into 'master'

Halfedge vector and length

See merge request !67
9 jobs for master in 4 minutes and 58 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #77904
VS2015
VS2015-32-bit

00:01:19

passed #77903
VS2015
VS2015-64-bit

00:01:26

passed #77902
VS2017
VS2017-32-bit

00:01:24

passed #77901
VS2015
VS2017-64-bit

00:01:20

passed #77898
Linux
clang-c++11

00:04:46

passed #77900
Linux
cppcheck

00:03:50

passed #77905
Linux
doc

00:00:26

passed #77897
Linux
gcc-c++11

00:03:59

passed #77899
Apple
macos-c++11

00:03:10