YAML: correctly free yaml_event before reusing
YAML: Remove wrong comment
YAML: make it more obvious that we use LibYAML
YAML: don't use aliases/anchors for fixnums
YAML: expose libyaml's emitter options, use unicode mode by default
YAML: add output configuration options
YAML: tests for emitter-line-break variable
YAML: better docs for >yaml, typos
YAML: oops, fix according to help-lint