Copies the asset from sourceId into destinationId.
UsageReturns, destinationId, overwrite, callback)
sourceIdStringThe ID of the asset to copy.
destinationIdStringThe ID of the new asset created by copying.
overwriteBoolean, optionalOverwrite any existing destination asset ID.
callbackFunction, optionalAn optional callback. If not supplied, the call is made synchronously. The callback is passed an empty object and an error message, if any.