Update container to have ID provided by the user

Signed-off-by: Michael Crosby <michael@docker.com>

container.go

@@ -9,8 +9,8 @@ package libcontainer
 // be destroyed by a separate process, any function may return that the container
 // was not found.
 type Container interface {
-	// Returns the path to the container which contains the state
-	Path() string
+	// Returns the ID of the container
+	ID() string
 
 	// Returns the current run state of the container.
 	//

factory.go

@@ -12,14 +12,14 @@ type Factory interface {
 	// System error
 	//
 	// On error, any partially created container parts are cleaned up (the operation is atomic).
-	Create(path string, config *Config) (Container, error)
+	Create(id string, config *Config) (Container, error)
 
-	// Load takes the path for an existing container and reconstructs the container
+	// Load takes an ID for an existing container and reconstructs the container
 	// from the state.
 	//
 	// Errors:
 	// Path does not exist
 	// Container is stopped
 	// System error
-	Load(path string) (Container, error)
+	Load(id string) (Container, error)
 }