Merge meteor subscriptions into redux

[Chun-Yang]

1. use autorun to emit actions and update collection data in store
2. when we dispatch an action that require the data, we pass the data as part of the action
3. for param-store, we always pass the previous state into the action

[Chun-Yang]

Potential problem: performance penalty. We may subscribe to a lot of records. Since the state is not mutable, whenever we do an update, all of the data are re-written into memory.

TODO: need stress test.

Maybe we should keep meteor subscriptions out of the store.