Merge branch 'fix-warnings' into 'master'

Fix warnings

See merge request !48
9 jobs for master in 3 minutes and 51 seconds
Status Name Job ID Coverage
  Test
passed clang-c++11 #67823
Linux

00:03:50

passed cppcheck #67825
Linux

00:00:27

passed doc #67830
Linux

00:00:19

passed gcc-c++11 #67822
Linux

00:03:16

passed macos-c++11 #67824
Apple

00:01:39

passed VS2015-32-bit #67829
VS2015

00:01:09

passed VS2015-64-bit #67828
VS2015

00:01:21

passed VS2017-32-bit #67827
VS2017

00:01:13

passed VS2017-64-bit #67826
VS2015

00:01:47