Performance & standardization improvements.

Business logic fixes.
RecyclableQueue & RecyclableStack added - pending improvements.

Recyclable.Collections.Benchmarks/Program.cs

@@ -0,0 +1,8 @@
+using BenchmarkDotNet.Running;
+using Recyclable.Collections.Benchmarks;
+
+BenchmarkRunner.Run<ListVsLinkedListBenchmark>();
+//BenchmarkRunner.Run<DelegateVsComparerBenchmark>();
+
+//var tests = new ListVsLinkedListBenchmark();
+//tests.RecyclableList();