[Ready] SoundComponent (#164)

Requires https://github.com/space-wizards/space-station-14/pull/768

- [x] Play sounds
- [x] SoundSchedules actually work
- [x] Send sound to specific users
- [x] Make existing components use SoundComponent
- [x] Add ScheduledSounds from prototypes
- [x] Add Play methods equivalent to those of AudioSystem.
- [x] Document most code.

Content.Client/EntryPoint.cs

@@ -26,6 +26,7 @@ using SS14.Shared.IoC;
 using SS14.Shared.Prototypes;
 using System;
 using Content.Client.GameObjects.Components.Mobs;
+using Content.Client.GameObjects.Components.Sound;
 using Content.Client.UserInterface;
 using Content.Shared.GameObjects.Components.Markers;
 using Content.Shared.GameObjects.Components.Mobs;
@@ -82,6 +83,7 @@ namespace Content.Client
             factory.Register<DamageableComponent>();
             factory.Register<ClothingComponent>();
             factory.Register<ItemComponent>();
+            factory.Register<SoundComponent>();
 
             factory.RegisterReference<ClothingComponent, ItemComponent>();