Open links in background when ⌘ key is pressed (#1637)

When you hold down the meta key (⌘), and click on a link in a message,
the target application will not activate, so N1 will stay in the
foreground.
Electron only supports this for OS X

package.json

@@ -11,7 +11,7 @@
   "bugs": {
     "url": "https://github.com/nylas/N1/issues"
   },
-  "electronVersion": "0.36.7",
+  "electronVersion": "0.36.9",
   "dependencies": {
     "async": "^0.9",
     "atom-keymap": "^6.1.1",

src/components/evented-iframe.cjsx

@@ -151,7 +151,7 @@ class EventedIFrame extends React.Component
           target.setAttribute('href', "http://#{rawHref}")
 
       e.preventDefault()
-      NylasEnv.windowEventHandler.openLink(target: target)
+      NylasEnv.windowEventHandler.openLink(target: target, metaKey: e.metaKey)
 
   _isBlacklistedHref: (href) ->
     return (new RegExp(/^file:/i)).test(href)

src/window-event-handler.coffee

@@ -173,7 +173,7 @@ class WindowEventHandler
     event.preventDefault()
     event.stopPropagation()
 
-  openLink: ({href, target, currentTarget}) ->
+  openLink: ({href, target, currentTarget, metaKey}) ->
     if not href
       href = target?.getAttribute('href') or currentTarget?.getAttribute('href')
 
@@ -191,7 +191,7 @@ class WindowEventHandler
       href = encodeURI(decodeURI(href))
       remote.getGlobal('application').openUrl(href)
     else if schema in ['http:', 'https:', 'tel:']
-      shell.openExternal(href)
+      shell.openExternal(href, activate: !metaKey)
 
     return