Move and "publish" EchoArgs for the tests

* Move EchoArgs from test/EchoArgs to test/tools/EchoArgs
* Use "dotnet publish" for building EchoArgs in build.psm1 so the test
  can call it directly

test/tools/EchoArgs/EchoArgs.cs

@@ -0,0 +1,24 @@
+//---------------------------------------------------------------------
+// Author: Keith Hill
+//
+// Description: Very simple little console class that you can use to see
+//              how PowerShell is passing parameters to legacy console
+//              apps.
+//
+// Creation Date: March 06, 2006
+//---------------------------------------------------------------------
+using System;
+
+namespace Pscx.Applications
+{
+    class EchoArgs
+    {
+        static void Main(string[] args)
+        {
+            for (int i = 0; i < args.Length; i++)
+            {
+                Console.WriteLine("Arg {0} is <{1}>", i, args[i]);
+            }
+        }
+    }
+}

test/tools/EchoArgs/project.json

@@ -0,0 +1,28 @@
+{
+    "name": "echoargs",
+    "version": "1.0.0-*",
+    "description": "Very simple little console class that you can use to see how PowerShell is passing parameters to legacy console apps.",
+
+    "buildOptions": {
+        "emitEntryPoint": true
+    },
+
+    "frameworks": {
+        "netcoreapp1.0": {
+            "dependencies": {
+                "Microsoft.NETCore.App": "1.0.0"
+            }
+        }
+    },
+
+    "runtimes": {
+        "ubuntu.16.04-x64": { },
+        "ubuntu.14.04-x64": { },
+        "debian.8-x64": { },
+        "centos.7-x64": { },
+        "win7-x64": { },
+        "win81-x64": { },
+        "win10-x64": { },
+        "osx.10.11-x64": { }
+    }
+}