Copy/paste support

[dehydr8]

The packaged electron application doesn't support copy/paste and other editing functions because the menu items and bindings need to be explicitly added. Reference: electron/electron#2591

The menu items and bindings need to be added in app/layout/shell.js to enable support for the said functions.

[mike-goodwin]

As far as I can tell these editing functions do work via keyboard shortcuts (Ctrl-C etc.). Is this request to add a context (right-click) menu with the editing operations. I saw from your PR #40 that you were adding an edit submenu to the top menu bar. This doesn't seem to work because if you select the menu option, the edit box you were in loses focus. Which behaviour are you aiming for?

[dehydr8]

It works normally when we start the application using npm run start (triggers electron .) because it starts the app with electron's default menu items. But since we don't have these menu items in the packages application, Cmd+C and other keyboard shortcuts (on a mac) don't work.

[mike-goodwin]

So it fails on a Mac? OK, I should be getting a Mac to test on soon, as soon as I do I will get this addressed. Thanks for your contribution!

[mike-goodwin]

Merged in Pr #40