#44 Add support for UI font tags

[mattyj]

Maybe I couldn't find it, but it would be nice to have
support for defining reusable font attributes. Like
this:

<UI>
<Property Id="DefaultUIFont">Tahoma8</Property>
<TextStyle Id="Tahoma8" FaceName="Tahoma" Size="8" />
...
</UI>

Or:

<TextStyle Id="DlgFont8" FaceName="Tahoma" Size="8" />
<TextStyle Id="DlgFontBold8" FaceName="Tahoma"
Size="8" Bold="yes" />
<TextStyle Id="VerdanaBold13" FaceName="Verdana"
Size="13" Bold="yes" />

Stuff like that. Neat!