Update Cycle Core to v3

Author: Andre Medeiros

package.json

@@ -13,10 +13,10 @@
     "jsonp": "^0.2.0"
   },
   "peerDependencies": {
-    "@cycle/core": "2.x.x"
+    "@cycle/core": "3.x.x"
   },
   "devDependencies": {
-    "@cycle/core": "2.x.x",
+    "@cycle/core": "3.x.x",
     "babel": "5.8.x",
     "babelify": "6.1.x",
     "browserify": "11.0.1",