Improved persistence subsystem.

Now is more effisient and only performs the
persistence operations only when persistent
datata is changed (not the whole state atom)

frontend/uxbox/core.cljs

@@ -1,6 +1,7 @@
 (ns uxbox.core
   (:require [beicon.core :as rx]
-            [uxbox.state :as s]
+            [cats.labs.lens :as l]
+            [uxbox.state :as st]
             [uxbox.router :as rt]
             [uxbox.rstore :as rs]
             [uxbox.ui :as ui]
@@ -8,12 +9,24 @@
 
 (enable-console-print!)
 
+(defn main
+  "Initialize the storage subsystem."
+  []
+  (let [lens (l/select-keys [:pages-by-id
+                             :projects-by-id])
+        stream (->> (l/focus-atom lens st/state)
+                    (rx/from-atom)
+                    (rx/debounce 1000)
+                    (rx/tap #(println "[save]")))]
+    (rx/on-value stream #(dl/persist-state %))))
+
 (defonce +setup+
   (do
     (println "bootstrap")
 
+    (st/init)
     (rt/init)
     (ui/init)
 
     (rs/emit! (dl/load-data))
-    (rx/on-value s/stream #(dl/persist-state %))))
+    (main)))