* (bug 28586) YAML: strings that are the same as boolean literals

* (bug 28586) YAML: strings that are the same as boolean literals
* (bug 28591) Update/replace/supplement spyc (YAML parsing library)
* YAML API output is now 1.2 compliant, using JSON as the formatter

YAML 1.2 spec is a JSON subset - "The primary objective of this revision is to bring YAML into compliance with JSON as an official subset. YAML 1.2 is compatible with 1.1 for most practical applications - this is a minor revision." [1] Per discussion with Tim, switch YAML to use the JSON formatter

Was originally going to delete the ApiFormatYaml per Tim, but class needed to keep nicer (and apparent) output in API help page

Hence made subclass ApiFormatJson, minimal method overriding

spyc.php deleted from libs

[1] http://www.yaml.org/spec/1.2/spec.html#id2803629