Fixed #12.

Apparently, when you return to the app, the HttpRequests returns a null response, on which you obviously can't Get a ResponseStream.
Added a 300x300 logo.
Moved a bit of code from Tiles to MainPage.

A ScheduledAgent is not permitted to use certain APIs (in this case: adding a tile, adding an updater), so the Base dll used by the agent may not use these as well.
Miscellaneous stuff in prepare for release.

That didn't come out quite right. I mean, RELEASE!!!