Enable many clang warnings and fix violations

9 jobs for adjust-compiler-warnings in 4 minutes and 20 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #75758
VS2015
VS2015-32-bit

00:01:16

passed #75757
VS2015
VS2015-64-bit

00:01:25

passed #75756
VS2017
VS2017-32-bit

00:01:09

passed #75755
VS2015
VS2017-64-bit

00:01:27

passed #75752
Linux
clang-c++11

00:04:15

passed #75754
Linux
cppcheck

00:04:19

passed #75759
Linux
doc

00:00:19

passed #75751
Linux
gcc-c++11

00:02:45

passed #75753
Apple
macos-c++11

00:02:59