lavd/xv: keep aspect ratio

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
lavd/xv: add window id param

Device is able to use existing window, that can be a
part of existing GUI - instead of newly created one.

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
lavd/xv: implement repaint message

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
Merge remote-tracking branch 'lukaszmluki/master'

* lukaszmluki/master:
  lavd/xv: implement repaint message
  lavd/xv: add window id param
  lavd/xv: keep aspect ratio

Merged-by: Michael Niedermayer <michaelni@gmx.at>