Minimal cmake version raised to 3.1

11 jobs for cleanups in 3 minutes and 47 seconds
Status Job ID Name Coverage
  Test
passed #54678
VS2013
VS2013-32-bit

00:00:55

passed #54677
VS2013
VS2013-64-bit

00:00:55

passed #54676
VS2015
VS2015-32-bit

00:01:18

passed #54675
VS2015
VS2015-64-bit

00:01:07

passed #54674
VS2017
VS2017-32-bit

00:01:27

passed #54673
VS2015
VS2017-64-bit

00:01:15

passed #54670
Linux
clang-c++11

00:03:27

passed #54672
Linux
cppcheck

00:00:24

passed #54679
Linux
doc

00:00:20

passed #54669
Linux
gcc-c++11

00:03:46

passed #54671
Apple
macos-c++11

00:01:27