- Support reading files
    - Replace load() with load_string(), dump() with dump_string()
    - Support legacy interface functions Load, LoadFile, Dump
    - ... and --- are now correctly invalid in quoted scalars
    - Improve block scalar handling, passing two more tests
    - Improve multiline plain handling, passing another test
    - Partial implementation of flow style collections
    - Allow unicode in alias/anchor names
    - Document header at the end is now recognized
    - Support all valid escapes in double quotes
    - ...and forbid invalid ones
    - Multiline quoted strings must be indented
    - Forbid sequence or mapping as a mapping value on the same line
    - Forbit sequence after an anchor/tag on the same line