Repeated Feed Warning on AutoUpdate

When a large feed is loaded (> 2,000 events), like "7 Days, All Magnitudes U.S.", the feed warning dialog is shown. If autoUpdate is also enabled then the feed warning is shown every 60 seconds when the feed is reloaded via auto update.

We should only show the feed warning on the initial selection of the feed,

• when the application is loaded
• when the large feed is selected

We should not show the feed warning when auto update triggers a load.