Support Yaml Validation against Schema

[guy-lud]

Hello,

I wonder if you are planning to add Yaml Schema validation, now we have to convert it to json and validate the json.

[xoofx]

I'm not using SharpYaml these days, so I have little interest to invest on it, but PR welcome (though that sounds quite some work to do a full schema validation!)

[guy-lud]

Thank you for your answer