test: Localize tests output in one directory

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
img: Feed all opts into images object

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
img: Rename private var with _ prefix

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
img: Create images in dir specified by option

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
test: Put images into wdir, not into global path

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
test: Automatically cleanup and report whether things passed or not

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>