Change all references to "nodequeue" to queue and subqueue where appropriate

We refer in the interface to Nodequeues -- such as adding and removing them -- despite the fact that no such thing exists. We have only queues and subqueues. To avoid confusing for end users, developers, and everyone involved, we should change all instances of "Nodequeue" that don't refer specifically to the module, and better document the difference between queues and subqqueues.