Merge branch 'master' into xterm

* master: (62 commits)
  1.4.3
  Disable ia32 linux releases (#2164)
  Fixed writing composed characters (#2158)
  Doc: Add yarn install to contribute instructions (#2117)
  Change "Close Session" shortcut on Linux/Windows  (#2160)
  Notice for plugins (#2114)
  Updated dependencies to the latest version (#2146)
  1.4.2
  Reverted class names to as they were before (#2139)
  1.4.1
  AppVeyor environment variables are now on the platform (#2137)
  Brought back the icon for closing tabs (#2136)
  Brought back keymap documentation to the website (#2133)
  1.4.0
  Don't build on master, except for releases (#2132)
  Ensured that `async-retry` is added to the bundle (#2131)
  Ensure correct update channel is displayed in About window (#2130)
  Retry loading it if config doesn't exist in auto updater (#2129)
  Write contents of default config to hyper.js (#2128)
  Use a string for setting the update channel (#2127)
  ...