Remove Commands.Omi module

This was a temporary work-around that now needs to be removed (mostly
because the xUnit tests are out-of-date because we didn't have a runner,
and it's not worth it to fix them). Rather than let more cruft
accumulate, we need to remove it.

Resolves #551

test/csharp/test_OmiInterface.cs

@@ -1,71 +0,0 @@
-using Xunit;
-using System;
-using System.Management.Automation;
-using System.Diagnostics;
-using System.Collections.Generic;
-using System.Linq;
-using System.Xml.Linq;
-
-namespace PSTests
-{
-    public static class OmiInterfaceTests
-    {
-        [Fact]
-        public static void TestHostName()
-        {
-            const string ns = "root/omi";
-            const string cn = "OMI_Identify";
-            const string property = "SystemName";
-
-            string expected = null;
-
-            var startInfo = new ProcessStartInfo
-            {
-                FileName = @"/usr/bin/env",
-                Arguments = "hostname",
-                RedirectStandardOutput = true,
-                UseShellExecute = false
-            };
-            using (Process process = Process.Start(startInfo))
-            {
-                 // Get output of call to hostname without trailing newline
-                expected = process.StandardOutput.ReadToEnd().Trim();
-                process.WaitForExit();
-
-                // The process should return an exit code of 0 on success
-                Assert.Equal(0, process.ExitCode);
-            }
-
-            string value = null;
-            OmiInterface oi = new OmiInterface();
-            oi.GetOmiValue(ns, cn, property, out value);
-            Assert.Equal(expected, value);
-        }
-
-        [Fact]
-        public static void TestXHugeNumberEnumerable()
-        {
-            const string ns = "interop";
-            const string cn = "X_HugeNumber";
-
-            OmiInterface oi = new OmiInterface();
-            IEnumerable<XElement> elements;
-            oi.GetOmiValues(ns, cn, out elements);
-            Assert.True(elements.FirstOrDefault() != null);
-        }
-
-        [Fact]
-        public static void TestXHugeNumberOmiData()
-        {
-            const string ns = "interop";
-            const string cn = "X_HugeNumber";
-
-            OmiInterface oi = new OmiInterface();
-            
-            OmiData data;
-            oi.GetOmiValues(ns, cn, out data);
-            Assert.True(data != null);
-            Assert.Equal(data.Values.Count(), 22);
-        }
-    }
-}