added gzip after pipeline

NzbDrone.Api/Extensions/GZipPipeline.cs

@@ -0,0 +1,38 @@
+using System.IO;
+using System.IO.Compression;
+using System.Linq;
+using Nancy;
+
+namespace NzbDrone.Api.Extensions
+{
+    public static class GzipCompressionPipeline
+    {
+        public static void Handle(NancyContext context)
+        {
+            if (!context.Response.ContentType.Contains("image") && context.Request.Headers.AcceptEncoding.Any(x => x.Contains("gzip")))
+            {
+                var data = new MemoryStream();
+                context.Response.Contents.Invoke(data);
+                data.Position = 0;
+                if (data.Length < 1024)
+                {
+                    context.Response.Contents = stream =>
+                    {
+                        data.CopyTo(stream);
+                        stream.Flush();
+                    };
+                }
+                else
+                {
+                    context.Response.Headers["Content-Encoding"] = "gzip";
+                    context.Response.Contents = s =>
+                    {
+                        var gzip = new GZipStream(s, CompressionMode.Compress, true);
+                        data.CopyTo(gzip);
+                        gzip.Close();
+                    };
+                }
+            }
+        }
+    }
+}