add SPICE_SERVER_VERSION
add SPICE_SERVER_VERSION

Allow to ifdef features which depend on a certain libspice-server release.

fgouget/spice,Fantu/spice,elmarco/spice,ya-mouse/spice,freedesktop-unofficial-mirror/spice__spice,alon/spice-server,alon/spice-server,dezelin/spice,virtualAMP/spiceplay,mathslinux/spice,SPICE/spice,SPICE/spice,fgouget/spice,freedesktop-unofficial-mirror/spice__spice,mathslinux/spice,mathslinux/spice,fgouget/spice,freedesktop-unofficial-mirror/spice__spice,virtualAMP/spiceplay,dezelin/spice,ya-mouse/spice,Fantu/spice,alon/spice-server,alon/spice-server,elmarco/spice,freedesktop-unofficial-mirror/spice__spice,dezelin/spice,ya-mouse/spice,virtualAMP/spiceplay,elmarco/spice,dezelin/spice,Fantu/spice,Fantu/spice,alon/spice-server,fgouget/spice,SPICE/spice,mathslinux/spice,freedesktop-unofficial-mirror/spice__spice,virtualAMP/spiceplay,elmarco/spice,mathslinux/spice,dezelin/spice,elmarco/spice