• App: Fix unintentionally global/os-wide keyboard shortcuts (fix #930)
• App: Back & forward: expose standard shortcuts first & handle mac,
  keep old weird (Ctrl+[ and Ctrl+]) shortcuts for backward compat
• App: Properly hide Developer Tools when asked by flag (fix #842)
• Log a helpful error when failing to parse JSON arg (fix #928)
• Bump default Electron to 8.2.0
• Misc GitHub & Travis nits.