This watch was just a placeholder for future watching functionality, but it's
not currently used. The watching functionality itself also encourages
propogating mutable state and complects the indexing and ledger update
operation. I think we should instead use explicit function calls with persistent
values instead of mutable state to implement this functionality when we
eventually need it.

…ndex

This allows us to run only the integration tests with:

```
clojure -M:cljtest --focus-meta :integration
```