[macosx] Rework JavaFX accessibility support to use OS X 10.10 SDK NSAccessibility Protocol

  The Mac Swing accessibility support needs to be updated to the OS X 10.10 SDK NSAccessibility Protocol. The API currently in use is 10.9, much of which has been deprecated by 10.10.

  There is no planned date to remove the old API, primarily due to binary compatibility, but to prevent future breakage the code should be reworked to use the new 10.10 NSAccessibility Protocol.