Adapt window management to chrome app window api

Appify tabs, windows, browserAction

Port the extension.windows.focus function to new window api and
generalize its error handling in the case where the requested window
does not exist. An error will be passed to the callback.

Port extension.browserAction and rename it to the more generic
extension.onLaunched.

Use of the id option when opening a window ensures that attempting to
open a duplicate window merely focuses the existing window.

Finally, after registration, close the options window and open the
inbox.

Port extension.remove

js/options.js

@@ -80,10 +80,10 @@
 
                 var accountManager = new bg.textsecure.AccountManager();
                 accountManager.registerSecondDevice(setProvisioningUrl, confirmNumber, incrementCounter).then(function() {
-                    $('.modal-container').hide();
-                    $('#init-setup').hide();
-                    $('#setup-complete').show().addClass('in');
-                    initOptions();
+                    extension.windows.getCurrent(function(appWindow) {
+                        bg.openInbox();
+                        extension.windows.remove(appWindow.id);
+                    });
                 });
             }
         });