added stopwatch example

added requestAnimationFrame polyfill

moved raf logic into a subscription

separated logic into multiple files, all state lives in a global namespaced model, reset no longer sends multiple actions only one

examples/stopwatch/models/stopwatch.js

@@ -0,0 +1,34 @@
+const xtend = require('xtend')
+const raf = require('raf')
+
+module.exports = {
+  state: {
+    elapsed: 0,
+    startTime: 0,
+    start: false,
+    laps: []
+  },
+  reducers: {
+    start: (data, state) => xtend(state, { start: true, startTime: Date.now() - state.elapsed }),
+    stop: (data, state) => xtend(state, { start: false }),
+    update: (data, state) => xtend(state, { elapsed: data }),
+    reset: (data, state) => xtend(state, { startTime: Date.now(), elapsed: 0, laps: [] }),
+    add: (data, state) => xtend(state, { laps: state.laps.concat(data) })
+  },
+  effects: {
+    now: (data, state, send, done) => {
+      if (state.start) {
+        let elapsed = data - state.startTime
+        send('update', elapsed, done)
+      }
+    }
+  },
+  subscriptions: [
+    (send, done) => {
+      raf(function loop () {
+        send('now', Date.now(), done)
+        raf(loop)
+      })
+    }
+  ]
+}