Move the song only if we have an index

This fixes a NullReferenceException when selecting "Add To Playlist"
Limit the maximum allowed song preparation time to 10 seconds

This prevents mobile or YouTube songs from blocking the playback too
long
Fixed the playlist only accepting dropped items on an item
Fix the build
Where did that even come from
Move the playlist item in front of the target item
Move the move logic into the ViewModel and support moving items to the back of the playlist
Fix a test
Send the whole exception to Buddy
Release of version 2.3.2
Initial hack on the file transfer API
Properly find a matching message and file transfer client

Fixes #64

Previously, if a user disconnected and reconnected again, the ReplaySubject would replay every client again and the selector would select the first (disconnected) in the sequence
Use Observable.FromAsync
Omg whiteline
Add songs from a mobile device to the playlist
Wait on the data to arrive
Always push on a new task
Omgggggggggggggggg
Fix the song source serialization
Serialize the songs properly