[Wakefield, pure-wl-toolkit] Implement pure wayland based toolkit

XWayland server provides limited capabilities for X11 desktop applications. In order to get full support of the desktop features, we need to implement a pure Wayland client toolkit for java. Wayland architecture in many ways differs from X11, so we cannot reuse XAWT even for basic capabilities. The new toolkit should be implemented from scratch. See more info on the wiki (https://wiki.openjdk.java.net/display/wakefield/Pure+Wayland+toolkit+plan+proposal)