spice: initial opengl/virgl support, postcopy migration fix.

# gpg: Signature made Tue 23 Feb 2016 12:30:40 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/spice/tags/pull-spice-20160223-1:
  Postcopy+spice: Pass spice migration data earlier
  spice/gl: tweak debug messages.
  spice/gl: add unblock timer
  spice: add opengl/virgl/dmabuf support
  spice: reset cursor on resize
  egl-helpers: add functions for render nodes and dma-buf passing
  configure: add dma-buf support detection.
  spice: init dcl before registering qxl interface
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>