Update Readers/Writers for Buffers & Fixes bugs (#283)

- [X] Renames PacketReader to CircularBufferReader
- [X] Fixes bugs with CircularBufferReader
- [X] Adds CircularBufferWriter
- [X] Adds SpanWriter
- [X] Adds SpanReader

Bumps release version

Projects/Server.Tests/Utility/EncodingHelpers.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Text;
+
+namespace Server.Tests
+{
+    public static class EncodingHelpers
+    {
+        public static Encoding GetEncoding(string bodyname) =>
+            bodyname switch
+            {
+                "utf-8"    => Utility.UTF8,
+                "utf-16"   => Utility.UnicodeLE,
+                "utf-16BE" => Utility.Unicode,
+                _          => Encoding.ASCII
+            };
+    }
+}