Alternative style/format outlook

[Garry Yao]

Style combo item is not presented under the preview style of the each style definition (same with format combo), sometimes this isn't an option at all (seen on user request #6379), the editor should allow an alternative presentation to be provided in the following format:

	{
		name : 'Colored: White',
		element : 'span',
		styles : { 'color' : 'White' },
		displayHtml: '<span style="background-color:#000;color:#fff;">Colored:White</span>'
	}