Merge branch 'warnings' into 'master'

More work on compiler warnings

See merge request !64
9 jobs for master in 9 minutes and 58 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #76330
VS2015
VS2015-32-bit

00:01:12

passed #76329
VS2015
VS2015-64-bit

00:01:25

passed #76328
VS2017
VS2017-32-bit

00:01:10

passed #76327
VS2015
VS2017-64-bit

00:01:26

passed #76324
Linux
clang-c++11

00:03:58

passed #76326
Linux
cppcheck

00:00:28

passed #76331
Linux
doc

00:00:17

passed #76323
Linux
gcc-c++11

00:03:54

passed #76325
Apple
macos-c++11

00:01:40