Improve the cursor handling

The decorations now set the cursor without using QGuiApplication's
override cursor API, but by setting directly the InputDevice's cursor.
This way it changes the cursor of the relevant seat only, and it also
fixes a bug where the cursor did not change back to the arrow after
moving a window.

Change-Id: I68e8cb8ff2367674dc376694a696baceca645843
Reviewed-by: Andy Nichols <andy.nichols@digia.com>
Compositor Wayland-EGL: fix connection to releaseBuffer

The page flipper buffer types have changed and should be fixed accordingly.

Change-Id: I0995b41dfdc6fa2981b747f901be66a1b2c4dc8b
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Wayland compositor: only include Qt's generated protocol headers

The system may come with conflicting headers generated by wayland-scanner.

Change-Id: I1aef7e32683ab02d0712ee65970f010a86854e43
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>