Tokens not expanded when saving as UFO

[SimonC (Simon Cozens)]

This:

seems to get exported as:

### class:1:MathScriptUpperVS1 ###
@MathScriptUpperVS1 = [
### open class 'MathScriptUpperVS1' ###
$[name endswith "script-math.uv001" and case==upper]
### close class 'MathScriptUpperVS1' ###
];

[GeorgSeifert]

Fixed it.