Move paste to renderer

The ‘clipboard’ module works in the renderer without using the ’remote’
package. So we can eliminate one IPC call this way :)

main/shortcuts.js

@@ -5,7 +5,7 @@ module.exports = {
 var localShortcut = require('electron-localshortcut')
 
 function init (menu) {
-  // ⌘+Shift+F is an alternative fullscreen shortcut to the one defined in menu.js.
+  // ⌘+Shift+F is an alternative fullscreen shortcut to the ones defined in menu.js.
   // Electron does not support multiple accelerators for a single menu item, so this
   // is registered separately here.
   localShortcut.register('CmdOrCtrl+Shift+F', menu.toggleFullScreen)