Add hardmode-related commands

-/hardmode - starts hardmode and converts the world
-/stophardmode - sets hardmode state to false, does not revert world.

TShockAPI/Commands.cs

@@ -189,6 +189,8 @@ namespace TShockAPI
             add(Permissions.buff, Buff, "buff");
             add(Permissions.buffplayer, GBuff, "gbuff", "buffplayer");
             add(Permissions.grow, Grow, "grow");
+            add(Permissions.hardmode, StartHardMode, "hardmode");
+            add(Permissions.hardmode, DisableHardMode, "stophardmode", "disablehardmode");
         }
 
         public static bool HandleCommand(TSPlayer player, string text)
@@ -1104,6 +1106,16 @@ namespace TShockAPI
             }
         }
 
+        private static void StartHardMode(CommandArgs args)
+        {
+            WorldGen.StartHardmode();
+        }
+
+        private static void DisableHardMode(CommandArgs args)
+        {
+            Main.hardMode = false;
+        }
+
         #endregion Cause Events and Spawn Monsters Commands
 
         #region Teleport Commands

TShockAPI/Permissions.cs

@@ -138,6 +138,9 @@ namespace TShockAPI
         [Description("")]
         public static readonly string grow;
 
+        [Description("User can change hardmode state.")]
+        public static readonly string hardmode;
+
         static Permissions()
         {
             foreach (var field in typeof(Permissions).GetFields())