added ability to remove a transaction rule.

src/cljc/auto_ap/utils.cljc

@@ -31,6 +31,19 @@
       replaced
       (into [x] replaced))))
 
+(defn merge-by [xs f x]
+  (let [found? (atom false)
+        replaced (mapv
+                  (fn [t]
+                    (if (= (f t) (f x))
+                      (do (reset! found? true)
+                          (merge t x))
+                      t))
+                  xs)]
+    (if @found?
+      replaced
+      (into [x] replaced))))
+
 (defn dollars-0? [amt]
   (< -0.001 amt  0.001))