some thumbnails show broken on initial channel load

[jessopb]

When loading a channel the speech instance has not loaded before, thumbnails are hit and miss, and show up broken.

[jessopb]

getClaimAndServeAsset() asks local db.File for a fileRecord, which fails on first request. It sets NO_FILE which causes 307 redirect to api/claim/get{$claimName}/${claimId}). claimGet() completes the get and returns success, but the NO_FILE error never actually tries serveAsset after initiating claimGet().

[jessopb]

For images, we're using the actual claim (embedUrl), rather than the external thumbnail url, which means that showing even the channel page means downloading all claims that are images in that channel. This will have to be checked against pagination: A channel with 1000 images could pose a problem if it gets all of them at once.

[jessopb]

I have some concern whether it's wise to implement the "get all image claims on this page" solution before connection management is in the sdk. We may just ensure a default thumbnail (rather than a broken one) is displayed, for now. Comments?