fix(package): update zen-observable to version 0.8.10

Closes #9

Author: greenkeeper[bot]

package.json

@@ -34,6 +34,6 @@
     "ramda": "^0.23.0",
     "tcomb": "^3.2.6",
     "ws": "^1.1.1",
-    "zen-observable": "^0.4.0"
+    "zen-observable": "^0.8.10"
   }
 }