* Adds the SoundSystem static proxy class for the AudioSystem.
Added a shared IAudioSystem interface for the future.
* Moved ConnectedClient property from IPlayerSession down to ICommonSession.
* Connected up the SoundSystem to the client/server AudioSystems.
* Converted client calls over to the new system.
* Marked the old serverside functions to play sound obsolete, use the new ones from the IAudioSystem.
* Added ISharedPlayerManager to the IoC registration.
* Removed IBaseSession, pushed all members down to ICommonSession.
* Pulled all members of client IPlayerSession into ICommonSession.
Marked client IPlayerSession as obsolete, use the base ICommonSession.
* Restricted setter access for properties in ICommonSession, only engine should be setting them.
* Fixed ping implementation on server.
* Moved AttachedEntityUid to ICommonSession.
* Added a shared IPlayerManager and pulled some common properties down to it.
* Added a shared player Filter class that holds a set of recipients in a networked call. Very useful for selecting recipients in a shared context.
* Removed the Interfaces folder.
* All objects inside the GameObjects subfolders are now in the GameObjects namespace.
* Added a Resharper DotSettings file to mark the GameObjects subfolders as not providing namespaces.
* Simplified Robust.client.Graphics namespace.
* Automated remove redundant using statements.
