add holdable, registered explosion and hook fixes

Barotrauma/BarotraumaServer/ServerSource/Lua/LuaClasses.cs

@@ -339,6 +339,12 @@ namespace Barotrauma
 				return item.GetComponent<Fabricator>();
 			}
 
+			public static Holdable GetHoldableComponent(Item item)
+			{
+				if (item == null) return null;
+				return item.GetComponent<Holdable>();
+			}
+
 			public static void DispatchRespawnSub()
 			{
 				GameMain.Server.RespawnManager.DispatchShuttle();
@@ -602,7 +608,8 @@ namespace Barotrauma
 				{
 					try
 					{
-						lastResult = env.lua.Call(hf.function, args);
+						if (hf.function is Closure)
+							lastResult = env.lua.Call(hf.function, args);
 					}
 					catch (Exception e)
 					{

Barotrauma/BarotraumaServer/ServerSource/Lua/LuaSetup.cs

@@ -204,6 +204,7 @@ namespace Barotrauma
 			UserData.RegisterType<WifiComponent>();
 			UserData.RegisterType<LightComponent>();
 			UserData.RegisterType<CustomInterface>();
+			UserData.RegisterType<Holdable>();
 			UserData.RegisterType<Inventory>();
 			UserData.RegisterType<CharacterInventory>();
 			UserData.RegisterType<Hull>();
@@ -221,6 +222,7 @@ namespace Barotrauma
 			UserData.RegisterType<ContentPackage>();
 			UserData.RegisterType<SubmarineInfo>();
 			UserData.RegisterType<SubmarineBody>();
+			UserData.RegisterType<Explosion>();
 
 			lua = new Script(CoreModules.Preset_SoftSandbox);