Fix Cast lazy loading

Move all the heavy initialization, which takes ~300ms, from require('./lib/cast') to Cast.init()

renderer/lib/cast.js

@@ -13,9 +13,8 @@ module.exports = {
   setRate
 }
 
-var airplayer = require('airplayer')()
-var chromecasts = require('chromecasts')()
-var dlnacasts = require('dlnacasts')()
+// Lazy load these for a ~300ms improvement in startup time
+var airplayer, chromecasts, dlnacasts
 
 var config = require('../../config')
 
@@ -33,6 +32,11 @@ function init (appState, callback) {
   state = appState
   update = callback
 
+  // Load modules, scan the network for devices
+  airplayer = require('airplayer')()
+  chromecasts = require('chromecasts')()
+  dlnacasts = require('dlnacasts')()
+
   state.devices.chromecast = chromecastPlayer()
   state.devices.dlna = dlnaPlayer()
   state.devices.airplay = airplayPlayer()

renderer/main.js

@@ -249,7 +249,7 @@ function dispatch (action, ...args) {
   }
 
   var handler = dispatchHandlers[action]
-  if (handler) handler.apply(null, args)
+  if (handler) handler(...args)
   else console.error('Missing dispatch handler: ' + action)
 
   // Update the virtual-dom, unless it's just a mouse move event