please review: RT-36335: [Accessibility] Hide prototype API

[Felipe Heidrich]

Hi,

Please review
https://javafx-jira.kenai.com/browse/RT-36335
http://cr.openjdk.java.net/~fheidric/RT36335/webrev/

Note: JDK 8u20 Build b18 is the last build in the 8u20 serie to include accessibility.
The accessibility code will be put back in the 8u-dev repo after the 8u20 fork, and it will be available again in the first 8u40 build.
We don’t have a build schedule for 8u40, but it should start a few weeks after the 8u20 fork.

Thanks
Felipe