Wallpaper setting download issues

[hugoalvarado]

Hello Redth,

I noticed the custom wallpaper setting was not working, so I made a few fixes. The main issue was a problem with the default filename path, since it was always null, and broke the http.DownloadData() call.

The Toast.MakeText was not working, but it did work in other screens, not sure why. I commented that out in the try/catch.

The apli level for the firetv stick is 17(android 4.2) but your project has 4.3 and 4.4. I set it back to 4.2. https://developer.amazon.com/public/solutions/devices/fire-tv/docs/device-and-platform-specifications

I was able to build and debug without problems using the basic xamarin licence, all thanks for your previous commit "Removed Newtonsoft.Json dependency".

Thank for this cool launcher!

-Hugo

[AndrewSav]

Woops, should have looked here first, before submitting mine https://github.com/Redth/FiredTVLauncher/pull/26

The deal with the toast is that it cannot be called from non-UI thread so it has to be wrapped into RunOnUiThread.