PCI device assignment is only supported in KVM's fork of qemu, so we
should really detect its availability and give a nice error if its
not supported.

* src/qemu_conf.[ch]: introduce QEMUD_CMD_FLAG_PCIDEVICE indicating
  that the -pcidevice command line option is available

* tests/*: update the tests

Add QEMUD_CMD_FLAG_NET_NAME to indicate that '-net ...,name=foo' is
supported and QEMUD_CMD_FLAG_HOST_NET_ADD to indicate that the
'host_net_add' monitor command is available.

Set both these flags if the qemu version is greater than 0.10.0.
Checking via the '-help' output would not work for the monitor command
and even for the command line arg, it would be quite fragile.

* src/qemu_conf.h: add new flags as aliases of QEMUD_CMD_FLAG_0_10

* src/qemu_conf.c: set QEMUD_CMD_FLAG_0_10 for versions >= 0.10.0

* tests/qemuhelptest.c: set QEMUD_CMD_FLAG_0_10 for the appropriate
  qemu versions

	* src/qemu_conf.c, src/qemu_conf.h: Use -vga or -std-vga
	when starting guests if video card is present
	* tests/qemuhelptest.c: Change to use constants instead
	of hardcoded hex numbers, and add VGA support
	* tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl-fullscreen.xml,
	tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl.args,
	tests/qemuxml2argvdata/qemuxml2argv-graphics-sdl.xml,
	tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-sasl.args,
	tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-sasl.xml,
	tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-tls.xml,
	tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc.xml,
	tests/qemuxml2argvdata/qemuxml2argv-input-xen.xml: Add <video>
	element for testing graphics adapter
	* tests/qemuxml2argvtest.c: Add QEMUD_CMD_FLAG_VGA flag
	* tests/qemuxml2xmltest.c: Add missing graphics-vnc-sasl/tls tests

Qemu < 0.10.0 did not support it, and virt-* tools now try to add this by
default, so it's extra important we ensure the option exists.

Signed-off-by: NMark McLoughlin <markmc@redhat.com>