Improvements

• Remove tooltip from custom buttons (86ffebf, #401, PR #421)
• Display G-code file name above the footer area (ff87053, #390, PR #422)
• [Electron][View Menu] Change "Home" to "View In Browser" (9fcddca)
• Update package dependencies (43e2b78, bfc8453 for Electron 4.0)
  • electron@~4.1.0
  • electron-builder@~20.39.0
  • electron-rebuild@~1.8.4
  • socket.io@~2.2.0
  • socket.io-client@~2.2.0