• macOS: Add tabs, used automatically instead of windows (PR #579).
  Provided by Electron and (so far) no available for Windows/Linux, contributions welcome.
• Fix #547 - Default to Electron 2.0.2 (including Chrome 61, Node 8.9.3, V8 6.1.534.41, GTK3 on Linux) (PR #587)
• Fix Gmail complaining window creation was prevented by a popup blocker (PR #603)
• Fix two build-time deprecation warnings