Merge remote-tracking branch 'remotes/kraxel/tags/pull-console-20150119-1' into staging

ui: add shared surface format negotiation.

# gpg: Signature made Mon 19 Jan 2015 12:47:36 GMT using RSA key ID D3E87138
# 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>"

* remotes/kraxel/tags/pull-console-20150119-1:
  ui/sdl2: Support shared surface for more pixman formats
  ui/sdl: Support shared surface for more pixman formats
  ui/gtk: Support shared surface for most pixman formats
  ui/spice: Support shared surface for most pixman formats
  ui/vnc: Support shared surface for most pixman formats
  ui/pixman: add qemu_pixman_check_format
  ui: Add dpy_gfx_check_format() to check backend shared surface support
  ui: Make qemu_default_pixman_format() return 0 on unsupported formats

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