Make sure that Internet Explorer CSS hacks are not removed

[kristerkari]

There are many CSS hacks that work for legacy Internet Explorer versions (http://codemug.com/html/css-hacks-for-ie6ie7ie8ie9-and-ie10/).

Currently CSSfmt turns this

.class {
  *zoom: 1;
  _width: 200px;
}

Into this:

.class {
  zoom: 1;
  width: 200px;
}