Open Notifications links in webview
Do not show "sign out" and "settings" menus in the webview
Use constants when setting bundle extra items.
Hide zoom buttons, and add the "up" button to the ActionBar.
Add the "custom" progress/loading indicator we already use in others webview within this app.
Merge pull request #370 from wordpress-mobile/issue/357-in-app-webview-notifications

Issue/357 in app webview notifications