yaml.h should be framework project only

Also update the project file to latest reccomendations.
Serialize YAML to a UTF8 string instead of double byte unicode
Allow generating YAML fragments
Modernize/ARCify YAMLSerialization
Merge remote-tracking branch 'sgrankin/master'

Conflicts:
	YAML.xcodeproj/project.pbxproj
iOSビルド設定を調整