Improve Waggle interoperability between Hive Web and Hive Android

[javgh]

Hive Android now also supports Waggle and Hive Android users can see Hive web users and vice versa.

The Waggle data record that Hive Android uploads will contain an extra "photo" field, if the user has a profile picture set. The picture is a PNG with a size of 200x200 at most (will be resized if necessary) and is Base64 encoded. The data record is about 100k, which isn't too bad, I think.

Hive Android will display those photos when showing Waggle search results.

Two things are still missing:

1. It would be nice, if Hive Web would also display those photos. It should be fairly straightforward, I think, to embed the image via a data url. The data should just be stripped for non-Base64 characters before embedding it into the web page, so that malicious search results can not inject any stuff into the web site.
2. Hive Android does not yet display Gravatars, even if they are available. Hive Web could either provide the Gravatar picture as photo data as well or - probably the better approach - Hive Android checks for Gravatar pictures on its own. I'll track that in a separate issue.