title: customize the style of javafx datepicker
body: <p>I am trying to avoid rolling my own JavaFX control if I could do this with either CSS or some code in main.java/controller.java.</p>
  
  <p>There is a button within the datepicker, which shows a calander icon, I want to change it to display an image.
  I could do this to button using <code>-fx-graphic</code>. Is there an equivalent in datepicker?</p>
  
  <p>I also wants to know if the weekday could be modified. my Locale is Chinese, it shows "星期一","星期二" and so on. It is like "Weekday Monday", which is long and unnecessary. I want to change it to 一, 二, etc. It is equivalent to Mon, Tue, etc.</p>
  
  <p>Is there anyway to do this? if CSS could not do it. 
  Could this be done using reflection and set string value?</p>