Stylesheet parsing error

Empty values in the stylesheet broke the tokenizing process, e.g. on:

    text-shadow: none /*{a-bar-shadow-x}*/  /*{a-bar-shadow-y}*/  /*{a-bar-shadow-radius}*/  /*{a-bar-shadow-color}*/;`

This created incorrect tokens like:

    a-bar-shadow-x}*/  /*{a-bar-shadow-y

This resulted in corrupt swatches.