Allow tube nodes to specify the runner class to use. Use the AsyncRunner for Tube Nodes within ZMQRunner/AsyncRunner

[sneakers-the-rat]

We just sort of lazily hardcoded using the SyncRunner for tube nodes.

we should actually allow tube nodes to specify what runner they should use i think.

• add a name field to TubeRunners
• allow runners to be looked up by name
• replace the place in CLI where we assign shortnames to runners with their tube names
• use the specified name in a tube node's params to run the tube
• if none is specified, within the zmq runner and async runner use the async runner