vnc: fix use-after-free.
sdl2: gles support.
vfio-display: add reset support.

# gpg: Signature made Fri 27 Apr 2018 10:54:17 BST
# gpg:                using RSA key 4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/ui-20180427-pull-request:
  ui: introduce vfio_display_reset
  console: introduce dpy_gfx_update_full
  sdl: Allow OpenGL ES context creation
  sdl: Move DisplayOptions global to sdl2_console
  qapi: Parameter gl of DisplayType now accept an enum
  vnc: fix use-after-free
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>