merge revision(s) r44809,r44813,r44815,r44816,r44817,r44818,r44918: [Backport #9481]

	* ext/psych/yaml/emitter.c: merge libyaml 0.1.5

	* ext/psych/yaml/loader.c: ditto

	* ext/psych/yaml/parser.c: ditto

	* ext/psych/yaml/reader.c: ditto

	* ext/psych/yaml/scanner.c: ditto

	* ext/psych/yaml/writer.c: ditto

	* ext/psych/yaml/yaml_private.h: ditto


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@44988 b2dd03c8-39d4-4d8f-98ff-823fe69b080e