* Separate hidden window, with its own renderer process, for WebTorrent
(Must be a window. You cannot run WebRTC at all in a Web Worker, and you can't
run it well in a node process like the electron main process.)
* Disabled the create-torrent-modal for now. That gives us a consistent UX
regardless of whether the user dragged files or folders onto the app or opened
the Create New Torrent menu item.
* Main process routes all messages between the main and webtorrent windows.
* The renderer index.js is smaller now (but still too big), with the WebTorrent
interface moved to webtorrent.js / it's own process.
* The UI should be faster now, and should not lag under load.
If there’s an update, this would redownload it every 6 hours until the
app is restarted. We could fix it, but let’s just simplify this:
App updates are checked for on app startup only.
If app is running in “production” (i.e. it has been packaged), then it
will be invoked with one less argument.
WebTorrent.exe arguments
vs.
electron.exe /path/to/app arguments
We need to detect this to correctly handle command line arguments.
