Log Message:
libyaml: updated to 0.2.3

0.2.3:
* Fixed typo.
* Fix typo in comment
* Use pointer to const for strings that aren't/shouldn't be modified
* Squash a couple of warnings in example-deconstructor-alt
* Fix spelling for error message
* Make appveyor config be a hidden file
* Add CHANGES file
* Always output document end before directive (YAML 1.2 compatibility)
* Output document end marker after open ended scalars
* change cmake target name from libOFF.a to libyaml.a
* include/yaml.h: fix comments
* Fixed missing token in example
* Avoid recursion in the document loader.
* Support %YAML 1.2 directives
* Change dllexport controlling macro to use _WIN32