Add support for setting http referrer

- Add url option to specify the http referrer
- Add httpReferrer attribute to webview

NOTE: This is still not complete. Some love has to be done to
guest-view-manager.coffee and very likely the function calls called
createGuest and to the code that uses them.

atom/browser/api/lib/browser-window.coffee

@@ -11,6 +11,8 @@ BrowserWindow::__proto__ = EventEmitter.prototype
 BrowserWindow.windows = new IDWeakMap
 
 BrowserWindow::_init = ->
+  @urlOptions = {}
+
   # Simulate the application menu on platforms other than OS X.
   if process.platform isnt 'darwin'
     menu = app.getApplicationMenu()
@@ -84,14 +86,23 @@ BrowserWindow.fromId = (id) ->
   BrowserWindow.windows.get id
 
 # Helpers.
-BrowserWindow::loadUrl = -> @webContents.loadUrl.apply @webContents, arguments
+BrowserWindow::loadUrl = ->
+  args = [].slice.call arguments
+  unless args.length > 1
+    args.push @urlOptions
+
+  #TODO: This needs fixing!
+  @urlOptions = args[1]
+
+  @webContents.loadUrl.apply @webContents, args
+
 BrowserWindow::send = -> @webContents.send.apply @webContents, arguments
 
 # Be compatible with old API.
 BrowserWindow::restart = -> @webContents.reload()
 BrowserWindow::getUrl = -> @webContents.getUrl()
-BrowserWindow::reload = -> @webContents.reload()
-BrowserWindow::reloadIgnoringCache = -> @webContents.reloadIgnoringCache()
+BrowserWindow::reload = -> @webContents.reload(@urlOptions)
+BrowserWindow::reloadIgnoringCache = -> @webContents.reloadIgnoringCache(@urlOptions)
 BrowserWindow::getPageTitle = -> @webContents.getTitle()
 BrowserWindow::isLoading = -> @webContents.isLoading()
 BrowserWindow::isWaitingForResponse = -> @webContents.isWaitingForResponse()