Add additional hooks to resources

[abeham]

The desmod package builds on top of SimPy and adds some additional components and events that processes can hook to which may be very nice for Sim# as well:

• when_any is a hook that triggers when a store contains an object
• when_full is a hook that triggers when a store is full
• when_new is a hook that triggers when a new item is added to the store

when_any and when_full could be translated for ResourcePool as well. Even Container could be enhanced with some of these hooks.

Additionally, desmod specifies a PriorityQueue (PriorityStore) which would dequeue items in priority order.

[abeham]

Add PriortiyStore and perform some refactorings in 14c69d18c8469e92bb2982fd33689753b91aac9c