clj patterns

[mhuebert]

This branch is for adding support for "patterns" in Clojure.

• re-use the data structure as we use in cljs for recording pattern dependencies, eg {e {a {v <node>}}}
• ability to run a query while also setting up dependencies on all the patterns that should invalidate it
• registry: {...pattern #{queries}}
• registry: {query #{listeners}}
• invalidation: loop through a list of datoms (from tx-report) and find any queries that are invalid - recompute the result & send to all listeners
• clean-up queries when last listener unlistens

TBD - figure out how similar things should work in Clojure vs ClojureScript (since Reagent doesn't work in Clojure but we probably want to keep using it in the client)