[OpenJDK 2D-Dev] RFR: 8198991: Move Java2D demo to the open repository

[Philip Race]

Bug: https://bugs.openjdk.java.net/browse/JDK-8198991
Webrev: http://cr.openjdk.java.net/~prr/8198991/

This moves the Java 2D demo from "closed" to "open".
It is now called "J2Ddemo" to avoid any trademark questions.
This has already been reviewed internally and the images here are OK to 
keep.

-phil.