Move LocalServer to core library
JoinVoice handling
Manually register messages for iOS
Drop ServerPingMessage
Set online status automatically
Add ChatHistory
Catch up core

 - Drop MVVMLight (need iOS/Android support)
 - Tweak SQLite to work on iOS
 - Various messages / view model additions/improvements
Add iOS client start
Add GroupView / ChatWindow
Setup ChatHistory
Switch MDX for SharpDX