Create new video driver API that has a per-instance context structure
and does not rely on keeping status in global or static variables.
Existing drivers are not yet converted to this API; instead there is a
wrapper which translates calls to them.
In the new API, an old API call vo_functions->xyz(args) is generally
replaced by vo_xyz(vo_instance, args).
The changes to keep the vesa, dxr2 and xover drivers compiling have
not been tested.
Uoti Urpala
2bcfe1e077