Fix paths unable to be created on Windows

core/src/main/java/com/seibel/distanthorizons/core/api/internal/ClientPluginChannelApi.java

@@ -55,7 +55,7 @@ public class ClientPluginChannelApi
 	
 	private void onCurrentLevelKeyMessage(CurrentLevelKeyMessage msg)
 	{
-		if (!msg.levelKey.matches("^(?=.{1,50}$)([a-zA-Z0-9-_]+@)?[a-zA-Z0-9-_]+(:[a-zA-Z0-9-_]+)?$"))
+		if (!msg.levelKey.matches("^[a-zA-Z0-9-_@]{1,50}$"))
 		{
 			throw new IllegalArgumentException("Server sent invalid level key.");
 		}

core/src/main/java/com/seibel/distanthorizons/core/wrapperInterfaces/world/IServerLevelWrapper.java

@@ -41,7 +41,7 @@ public interface IServerLevelWrapper extends ILevelWrapper
 			
 			if (!levelKeyPrefix.isEmpty())
 			{
-				return levelKeyPrefix + "@" + dimensionName;
+				return levelKeyPrefix + "@" + dimensionName.replace(":", "@@");
 			}
 		}