Delete the python xdg dependency.

BUG=RH#980749

Review URL: https://codereview.appspot.com/10930043
wayland: Add wayland support
wayland: add an example UI based on gtk3
wayland: Add README-wayland.md
Fix build of Wayland client

Added missing wayland-scanner files and Makefile rules

Signed-off-by: Eduardo Lima (Etrunko) <eduardo.lima@intel.com>
wayland: Use "key" request when a key event is not processed

The "keysym" request should not be used for normal text input.
Instead, "key" request should be sent to the context.