add flate filter to compress truetype font in output and fix some structure issues for pdf verification

src/UglyToad.PdfPig.Tests/Filters/FlateFilterTests.cs

@@ -0,0 +1,28 @@
+namespace UglyToad.PdfPig.Tests.Filters
+{
+    using System.Collections.Generic;
+    using System.IO;
+    using PdfPig.Filters;
+    using PdfPig.Tokens;
+    using Xunit;
+
+    public class FlateFilterTests
+    {
+        private readonly FlateFilter filter = new FlateFilter(new DecodeParameterResolver(new TestingLog()), new PngPredictor(), new TestingLog());
+
+        [Fact]
+        public void EncodeAndDecodePreservesInput()
+        {
+            var parameters = new DictionaryToken(new Dictionary<NameToken, IToken>());
+            var input = new byte[] {67, 69, 69, 10, 4, 20, 6, 19, 120, 64, 64, 64, 32};
+
+            using (var inputStream = new MemoryStream(input))
+            {
+                inputStream.Seek(0, SeekOrigin.Begin);
+                var result = filter.Encode(inputStream, parameters, 0);
+                var decoded = filter.Decode(result, parameters, 0);
+                Assert.Equal(input, decoded);
+            }
+        }
+    }
+}