Implement python podman create and start

- Added alias 'container()' to image model for CreateContainer()
- Fixed return in containers_create.go to wrap error in varlink
  exception
- Added a wait time to container.kill(), number of seconds to wait
  for the container to change state
- Refactored cached_property() to use system libraries
- Refactored tests to speed up performance

Signed-off-by: Jhon Honce <jhonce@redhat.com>

Closes: #821
Approved by: rhatdan

pkg/varlinkapi/containers_create.go

@@ -41,7 +41,7 @@ func (i *LibpodAPI) CreateContainer(call ioprojectatomicpodman.VarlinkCall, conf
 
 	newImage, err := runtime.ImageRuntime().New(ctx, config.Image, rtc.SignaturePolicyPath, "", os.Stderr, nil, image.SigningOptions{}, false, false)
 	if err != nil {
-		return err
+		return call.ReplyErrorOccurred(err.Error())
 	}
 	data, err := newImage.Inspect(ctx)