* 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
