Update to VS2013 and submodule repair.
Dropping support for Windows Phone 7
Removing Sharpserializer, use instead nuget package
Use Tweetsharp-PCL
Adapt TweetLoader to new Tweetsharp

Conversations left for later.
Adapt ScheduledAgent to TS-PCL.

Changes pending yet.
UserTokenFiller adaptation.
Adapt UsernameProvider
Adapt conversations.
Use StatusCode in ExtendedListbox messages
Adapt Tweetsharp for Ocell.
Minor error on TwitterOAuth.
Adapting Ocell.Phone8 to changes in TS-PCL.
Configure hash function for AsyncOAuth
Nasty mistake (it caused an StackOverflow exception)
Use SendTweetOptions
Library/packages tweaks.
Merge branch 'feature/tweetsharp-pcl' into develop