function coerceData (data) {
  data = utils.clone(data);
  if (data.lineHeight !== undefined) {
    data.lineHeight = parseFloat(data.lineHeight);
    if (!isFinite(data.lineHeight)) { data.lineHeight = undefined; }
  }
  if (data.width !== undefined) {
    data.width = parseFloat(data.width);
    if (!isFinite(data.width)) { data.width = undefined; }
  }
  return data;
}
Coerce some data to numbers.
as they will be passed directly into text creation and update