Added built-in plugin copying

src/Artemis.Core/Extensions/DirectoryInfoExtensions.cs

@@ -0,0 +1,15 @@
+using System.IO;
+
+namespace Artemis.Core.Extensions
+{
+    public static class DirectoryInfoExtensions
+    {
+        public static void CopyFilesRecursively(this DirectoryInfo source, DirectoryInfo target)
+        {
+            foreach (var dir in source.GetDirectories())
+                CopyFilesRecursively(dir, target.CreateSubdirectory(dir.Name));
+            foreach (var file in source.GetFiles())
+                file.CopyTo(Path.Combine(target.FullName, file.Name));
+        }
+    }
+}