Add event logging to libpod, even display to podman

In lipod, we now log major events that occurr.  These events
can be displayed using the `podman events` command. Each
event contains:

* Type (container, image, volume, pod...)
* Status (create, rm, stop, kill, ....)
* Timestamp in RFC3339Nano format
* Name (if applicable)
* Image (if applicable)

The format of the event and the varlink endpoint are to not
be considered stable until cockpit has done its enablement.

Signed-off-by: baude <bbaude@redhat.com>

libpod/container_commit.go

@@ -8,6 +8,7 @@ import (
 	"github.com/containers/buildah"
 	"github.com/containers/buildah/util"
 	is "github.com/containers/image/storage"
+	"github.com/containers/libpod/libpod/events"
 	"github.com/containers/libpod/libpod/image"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -177,5 +178,6 @@ func (c *Container) Commit(ctx context.Context, destImage string, options Contai
 	if err != nil {
 		return nil, err
 	}
+	defer c.newContainerEvent(events.Commit)
 	return c.runtime.imageRuntime.NewFromLocal(id)
 }