[tag syntax] let the writer override preset settings with attributes

[mavaddat]

From jekyll-cloudinary created by nhoizey: nhoizey#5

For example, let the writer use a verbose attribute in a Cloudinary Liquid tag, to have only this image manipulations verbose in the console when generating the site.

Or let the writer use min_width, max_width, steps and/or sizes attributes in a Cloudinary Liquid tag, to have a specific behaviour without needing any new preset in the _config.yml.