Merge branch 'improve-docs' into 'master'

Improve docs

See merge request !46
9 jobs for master in 6 minutes and 40 seconds (queued for 35 seconds)
Status Name Job ID Coverage
  Test
passed clang-c++11 #67387
Linux

00:03:50

passed cppcheck #67389
Linux

00:00:40

passed doc #67394
Linux

00:00:21

passed gcc-c++11 #67386
Linux

00:03:17

passed macos-c++11 #67388
Apple

00:01:40

passed VS2015-32-bit #67393
VS2015

00:01:15

passed VS2015-64-bit #67392
VS2015

00:01:15

passed VS2017-32-bit #67391
VS2017

00:01:18

passed VS2017-64-bit #67390
VS2015

00:01:16