tightened the formatter API as bit: CSS classes and CSS styles should be set via the `cellMetaInfo/rowMetaInfo.cellCss` and `ditto.cellStyles` arrays rather than patching them directly via `ditto.attributes.css` and/or `ditto.attributes.style` attributes of the same structure which is passed into the formatter: the latter (`.attributes`) is provided to allow custom formatters to tweak arbitrary HTML DOM node attributes (e.g. `data-xyz` attributes via `cellMetaInfo.attributes['data-xyz']='bugger millenium hand and shrimp';`) ... but not the DOM node's CSS classes or CSS styles.