yet another golang library for YAML support

 YAML library for the Go language.
 This adds some features compared to the golang standard YAML library.
  * Pretty format for error notifications
  * Supports Scanner or Lexer or Parser as public API
  * Supports Anchor and Alias to Marshaler
  * Allow referencing elements declared in another file via anchors
  * Extract value or AST by YAMLPath (like a JSONPath)