Re-implement chat in content. (#198)

* OOC is a word.

* Re-implement chat in content.

Content.Shared/Chat/ChatChannel.cs

@@ -0,0 +1,54 @@
+using System;
+
+namespace Content.Shared.Chat
+{
+    /// <summary>
+    ///     Represents chat channels that the player can filter chat tabs by.
+    /// </summary>
+    [Flags]
+    public enum ChatChannel : byte
+    {
+        None = 0,
+
+        /// <summary>
+        ///     Chat heard by players within earshot
+        /// </summary>
+        Local = 1,
+
+        /// <summary>
+        ///     Messages from the server
+        /// </summary>
+        Server = 2,
+
+        /// <summary>
+        ///     Damage messages
+        /// </summary>
+        Damage = 4,
+
+        /// <summary>
+        ///     Radio messages
+        /// </summary>
+        Radio = 8,
+
+        /// <summary>
+        ///     Out-of-character channel
+        /// </summary>
+        OOC = 16,
+
+        /// <summary>
+        ///     Visual events the player can see.
+        ///     Basically like visual_message in SS13.
+        /// </summary>
+        Visual = 32,
+
+        /// <summary>
+        ///     Emotes
+        /// </summary>
+        Emotes = 64,
+
+        /// <summary>
+        ///     Unspecified.
+        /// </summary>
+        Unspecified = 128,
+    }
+}