LCD font smoothing should be turned off on Mac

In 2.1 we added support for LCD font smoothing. This is amazing on Windows but looks worse than Greyscale smoothing on Mac. So for now we should turn this off by default on Mac. In the future we should support native rasterization on Mac as well then LCD will look good and we can turn it back on by default. I have filled RT-19040 for adding native rasterization support.

My suggestion for how to fix this is to add a Ant task in the Mac build process to replace all instances of "LCD" in the caspian.css file with "GreyScale". Something like:

<replace file="rt/javafx-ui-controls/src/com/sun/javafx/scene/control/skin/caspian/caspian.css">
  <replacetoken>lcd</replacetoken>
  <replacevalue>gray</replacevalue>
</replace>