Possible to declare any font style to style sheet.

Idea is to be able to declare a font with a broader range of
styles than simply italic/bold/bold italic something like this:

font-family: "Minion Pro"
font-style: "Bold Condensed"

At the moment, font-style only takes the values normal, italic and
oblique. In theory you should be able to get most members of a family by
way of font-style and font-weight, but this still doesn't allow access to
e.g. condensed variants, which are not accessed directly by way of
font-style or font-weight.

So to provide the same level of access to fonts via QSS as via Qt's direct
QFont APIs, we need the ability to set the font family name and then the
font style independently of the current font-style and font-weight
options.