Added extension methods

ExaArrayTests/ExaArray1DTests.cs

@@ -540,7 +540,12 @@ namespace ExaArrayTests
                 exPerf.Extend(3 * MAX); // more than one chunk
                 
                 var next = ExaArray1D<byte>.CreateFrom(exPerf, 0, exPerf.Length - 1);
+                var next2 = exPerf.Clone();
+                var next3 = exPerf.Clone(0, exPerf.Length - 1);
+                
                 Assert.That(next.Length, Is.EqualTo(exPerf.Length));
+                Assert.That(next2.Length, Is.EqualTo(exPerf.Length));
+                Assert.That(next3.Length, Is.EqualTo(exPerf.Length));
             }
 
             [Test]