Feature/refresh button

Adds refresh button. Light refactor of network query batch request code, so that the same set of network queries can be initiated in batches from more than one location. See NetworkTaskCollectionRunner. This class also offers an overridable handleResults method to support context-specific data handling.

Displays loading spinner and custom message when Refresh button has been pressed.

NOTE: in order to use the app on the emulator, you must send the GPS coordinates manually through DDMS pane when you click "Refresh". It works the same as when you provide your initial location at the landing page. On a real device with network features enabled, this won't be an issue.