Remove the dependency on System.ValueTuple (#63)

* Add an option to get tuple data via reflection.

* Removed non-relfection-based way of getting information about the tuples.

* Make methods static back.

* Remove the nuget dependency to System.ValueTuple

test/Ben.Demystifier.Benchmarks/Exceptions.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using BenchmarkDotNet.Attributes;
 using BenchmarkDotNet.Attributes.Jobs;
@@ -14,5 +15,26 @@ namespace Ben.Demystifier.Benchmarks
 
         [Benchmark(Description = "Demystify().ToString()")]
         public string Demystify() => new Exception().Demystify().ToString();
+
+        [Benchmark(Description = "(left, right).ToString()")]
+        public string ToStringForTupleBased() => GetException(() => ReturnsTuple()).ToString();
+
+        [Benchmark(Description = "(left, right).Demystify().ToString()")]
+        public string ToDemystifyForTupleBased() => GetException(() => ReturnsTuple()).Demystify().ToString();
+
+        private static Exception GetException(Action action)
+        {
+            try
+            {
+                action();
+                throw new InvalidOperationException("Should not be reachable.");
+            }
+            catch (Exception e)
+            {
+                return e;
+            }
+        }
+
+        private static List<(int left, int right)> ReturnsTuple() => throw new Exception();
     }
 }