Add that Menu.setApplication only works after 'ready' event.

I got caught on this while trying to add a menu in my application in OSX.
Redirect guest page's ipc message to embedder
spec: ipc-message event
doc: ipc-message event
Merge pull request #923 from ffdd/patch-1

Add that Menu.setApplication only works after 'ready' event.
Remove uses of deprecated APIs in remote module
Add sendToHost method
Upgrade brightray to fix crash in #393
Add "will-navigate" event for BrowserWindow
Add "will-navigate" event for WebContents
Redirect BrowserWindow's "will-navigate" event to WebContents
spec: "will-navigate" event
Merge pull request #924 from atom/webview-ipc-message

Add ipc-message event for <webview>
docs: "will-navigate" event
Merge pull request #931 from atom/will-navigate

Add "will-navigate" event
Bump v0.20.1
Use "http" for download url, fixes #929
Add "disablewebsecurity" attribute for <webview>
Set web preferences for guest page
spec: "disablewebsecurity" attribute