Updated the Stat Tracker to use System.Net.Http types.

Very similar to the previous Update Manager changes. The stat tracker now uses asynchronous threaded calls and manages exceptions better

TShockAPI/Extensions/ExceptionExt.cs

@@ -0,0 +1,27 @@
+using System;
+namespace TShockAPI.Extensions
+{
+	/// <summary>
+	/// Extensions for Exceptions
+	/// </summary>
+	public static class ExceptionExt
+	{
+		/// <summary>
+		/// Builds a formatted string containing the messages of the given exception, and any inner exceptions it contains
+		/// </summary>
+		/// <param name="ex"></param>
+		/// <returns></returns>
+		public static string BuildExceptionString(this Exception ex)
+		{
+			string msg = ex.Message;
+			Exception inner = ex.InnerException;
+			while (inner != null)
+			{
+				msg += $"\r\n\t-> {inner.Message}";
+				inner = inner.InnerException;
+			}
+
+			return msg;
+		}
+	}
+}