Merge ServiceHost xUnit test project into dev. (#5)

* Setup standard src, test folder structure.  Add unit test project.

* Actually stage the deletes.  Update .gitignore

src/ServiceHost/LanguageServer/SignatureHelp.cs

@@ -0,0 +1,42 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using Microsoft.SqlTools.EditorServices.Protocol.MessageProtocol;
+
+namespace Microsoft.SqlTools.EditorServices.Protocol.LanguageServer
+{
+    public class SignatureHelpRequest
+    {
+        public static readonly
+            RequestType<TextDocumentPosition, SignatureHelp> Type =
+            RequestType<TextDocumentPosition, SignatureHelp>.Create("textDocument/signatureHelp");
+    }
+
+    public class ParameterInformation
+    {
+        public string Label { get; set; }
+
+        public string Documentation { get; set; }
+    }
+
+    public class SignatureInformation
+    {
+        public string Label { get; set; }
+
+        public string Documentation { get; set; }
+
+        public ParameterInformation[] Parameters { get; set; }
+    }
+
+    public class SignatureHelp
+    {
+        public SignatureInformation[] Signatures { get; set; }
+
+        public int? ActiveSignature { get; set; }
+
+        public int? ActiveParameter { get; set; }
+    }
+}
+