[Proposal] IDE Serial settings window

I'm often moving between projects and having to change serial settings.

If the serial settings were in a splash screen this would make life easier, i.e. click on Serial Settings menu item, a new window opens up with all the board and port settings, click apply, window closes.

See also: http://forum.arduino.cc/index.php?topic=586357

Start by reviewing how the current Serial Settings menu works and read the linked Arduino forum discussion for context. Done means the IDE opens a separate Serial Settings window from the menu, exposes the board and port settings, applies changes, and closes the window.

Written by the indexing model from the issue text.