Add listenOnce to store
Warm up property streams

Bacon.js EventStreams are lazy, so if there are no listeners these properties won't be initialized.
Change how store.combine() works

Switch to Bacon.zipAsArray() so stream only fires after all combined streams had an event fire.
Add tests for createStore
1.1.0

- add tests
- add listenOnce to store's streaming props
- store's streaming props now capture events before external listeners are hooked up
- store.combine() now waits until all events have fired, providing grouped payloads in an array