Checkin for LivingSocial Assignment

Added following checks
1. If the app is running and the network is lost, show a toaster and
disable Settings menu.
2. If no network connectivity found don’t fetch the contents for the
list view

Additional enhancements which can be added but not applied for this app
1. The listener for network changes should be applied to all the
activities. In this case it would be SettingsActivity. For enhancement,
there can be a connection manager to which all the activities register.
2. The toaster messages can be externalized to support
internationalization