#10 move tokens to the root namespace for discoverability. upgrade xunit versions. there is a bug with test discovery for stringtokenizertests

src/UglyToad.PdfPig/Tokens/StreamToken.cs

@@ -0,0 +1,44 @@
+namespace UglyToad.PdfPig.Tokens
+{
+    using Filters;
+
+    internal class StreamToken : IDataToken<byte[]>
+    {
+        private readonly object lockObject = new object();
+
+        private byte[] decodedBytes;
+
+        public DictionaryToken StreamDictionary { get; }
+
+        public byte[] Data { get; }
+
+        public StreamToken(DictionaryToken streamDictionary, byte[] data)
+        {
+            StreamDictionary = streamDictionary;
+            Data = data;
+        }
+
+        public byte[] Decode(IFilterProvider filterProvider)
+        {
+            lock (lockObject)
+            {
+                if (decodedBytes != null)
+                {
+                    return decodedBytes;
+                }
+                
+                var filters = filterProvider.GetFilters(StreamDictionary);
+
+                var transform = Data;
+                for (var i = 0; i < filters.Count; i++)
+                {
+                    transform = filters[i].Decode(transform, StreamDictionary, i);
+                }
+
+                decodedBytes = transform;
+
+                return transform;
+            }
+        }
+    }
+}