ui: add support for -display spice-app
ui: gtk+sdl bugfixes.

# gpg: Signature made Fri 22 Feb 2019 07:53:13 GMT
# gpg:                using RSA key 4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full]
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>" [full]
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/ui-20190222-pull-request:
  display: add -display spice-app launching a Spice client
  spice: use a default name for the server
  qapi: document DisplayType enum
  build-sys: add gio-2.0 check
  char: register spice ports after spice started
  char: move SpiceChardev and open_spice_port() to spice.h header
  spice: do not stop spice if VM is paused
  spice: merge options lists
  spice: avoid spice runtime assert
  char/spice: discard write() if backend is disconnected
  char/spice: trigger HUP event
  ui/gtk: Fix the license information
  sdl2: drop qemu_input_event_send_key_qcode call
  spice: set device address and device display ID in QXL interface
  kbd-state: don't block auto-repeat events

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>