Add support for GZip and Deflate (#439)

* gzip - wip

* wip

* tests

* fix gzip and deflate

* CheckIfShouldKillVBCSCompiler

* DisableRequestBodyDecompressing

src/WireMock.Net/Util/CompressionUtils.cs

@@ -0,0 +1,49 @@
+using System;
+using System.IO;
+using System.IO.Compression;
+
+namespace WireMock.Util
+{
+    internal static class CompressionUtils
+    {
+        public static byte[] Compress(string contentEncoding, byte[] data)
+        {
+            using (var compressedStream = new MemoryStream())
+            using (var zipStream = Create(contentEncoding, compressedStream, CompressionMode.Compress))
+            {
+                zipStream.Write(data, 0, data.Length);
+
+#if !NETSTANDARD1_3
+                zipStream.Close();
+#endif
+                return compressedStream.ToArray();
+            }
+        }
+
+        public static byte[] Decompress(string contentEncoding, byte[] data)
+        {
+            using (var compressedStream = new MemoryStream(data))
+            using (var zipStream = Create(contentEncoding, compressedStream, CompressionMode.Decompress))
+            using (var resultStream = new MemoryStream())
+            {
+                zipStream.CopyTo(resultStream);
+                return resultStream.ToArray();
+            }
+        }
+
+        private static Stream Create(string contentEncoding, Stream stream, CompressionMode mode)
+        {
+            switch (contentEncoding)
+            {
+                case "gzip":
+                    return new GZipStream(stream, mode);
+
+                case "deflate":
+                    return new DeflateStream(stream, mode);
+
+                default:
+                    throw new NotSupportedException($"ContentEncoding '{contentEncoding}' is not supported.");
+            }
+        }
+    }
+}