Update to 5.2
Repair incompatibilities introduced with 5.1. The default Loader was changed, but
several methods like add_constructor still used the old default A more flexible fix for custom tag constructors Change default loader for yaml.add_constructor Change default loader for add_implicit_resolver, add_path_resolver
Make FullLoader safer by removing python/object/apply from the default FullLoader
Move constructor for object/apply to UnsafeConstructor
Fix bug introduced in 5.1 where quoting went wrong on systems with
sys.maxunicode <= 0xffff
Fix logic for quoting special characters