Complies with YAML Standard [5.4](https://yaml.org/spec/1.2.2/#54-line-break-characters) [25] instead of matching `\r` only in combination with `\n`.

Fixes issue #1053.

Properly resolves #1083, #996.

Also refactor the build action to use a matrix.

Add copying of shared library to the output directory with a test binary.

[binary] removed using of non unsigned char as argument at
'std::isspace' function that was provokes undefined behavior.

[.github/workflows/build.yml] enabled run of test at the
'windows-latest' environment.

This replaces the old Travis CI badge that didn't mean anything.

Partial revert of "Revert "Revert "Hide most of non-public symbols by default (#984)" (#1038)" (#1045)"

This reverts commit 0733aeb4.

GNUInstallDirs provided may be absolute paths, in which case appending
to the install prefix is not correct. We can instead use the provided
CMAKE_INSTALL_FULL_* variables, which are precomputed absolute paths.

https://cmake.org/cmake/help/latest/module/GNUInstallDirs.html

This reverts commit da1c8d36. and fixes #1036.

* Export YAML::detail::node::m_amount

The internal header node/detail/node.h is included by public headers;
YAML::detail::node is implemented in the header itself, and thus it gets
inlined... except for its static m_amount class member, which is
instantiated in the library only. Right now all the symbols of yaml-cpp
are exported (nothing is hidden), so the linker will find node::m_amount
in the yaml-cpp library.

As solution/workaround, explicitly export YAML::detail::node::m_amount.

* CMake: use GenerateExportHeader

Make use of the GenerateExportHeader CMake module to generate the dll.h
header with export macros.

While the produced dll.h is different, the result should be the same,
i.e. nothing changes for yaml-cpp or its users.

* CMake: hide all the symbols by default

Hide all the symbols that are not explicitly exported with YAML_CPP_API.
This way the ABI will be way smaller, and only actually exposing the
public classes/functions.

Removed the variable name in the defaulted function to make GCC happy.

convert.h line130 : warning C4244 conversation from int to T possible loss of data

* fix issue743: handle the empty content of flow sep/map correctly during emitting.

* handle the empty Tag/Anchor properly.

* delete comment

- Don't eagerly convert key to std::string
- Make const char* keys streamable when exception is thrown
- Don't create a temporary string when comparing a const char* key

Fixes #917

Fixes #501

Fixes #590.

Not use 'emit' as variable name, in Qt Framework it reserved word

For completeness I've implemented escaping for characters outside the
basic multilingual plane, but it doesn't get used (as there's no
EscapeAsAsciiJson emitter option implemented).

Per https://cmake.org/cmake/help/latest/policy/CMP0091.html, we need to
enable policy CMP0091 if we want to make use of MSVC_RUNTIME_LIBRARY
and/or CMAKE_MSVC_RUNTIME_LIBRARY.  Fixes issue #912.