Feature/save results as csv (#33)

* Code changes to save results as csv

*  changes to save resultset as csv

* removed csvHelper

* Retrieve right resultSet after batch execution]

* code clean up

* encode column names and use string.Join

* code review changes - property fix and rowBuilder removal

* changes to fix execution tests

* Code clean up

* Code clean up

* Test save as CSV

* Fix tests for Mac/Linux

* Add doc comment

* Add doc comments

* Delete file if exception occurs

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/Contracts/SaveResultsRequest.cs

@@ -0,0 +1,70 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using Microsoft.SqlTools.ServiceLayer.Hosting.Protocol.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts
+{
+    /// <summary>
+    /// Parameters for the save results request
+    /// </summary>
+    public class SaveResultsRequestParams
+    {
+        /// <summary>
+        /// The path of the file to save results in
+        /// </summary>
+        public string FilePath { get; set; }
+
+        /// <summary>
+        /// The encoding of the file to save results in
+        /// </summary>
+        public string FileEncoding { get; set; }
+
+        /// <summary>
+        /// Include headers of columns in CSV
+        /// </summary>
+        public bool IncludeHeaders { get; set; }
+
+        /// <summary>
+        /// Index of the batch to get the results from
+        /// </summary>
+        public int BatchIndex { get; set; }
+
+        /// <summary>
+        /// Index of the result set to get the results from
+        /// </summary>
+        public int ResultSetIndex { get; set; }
+
+        /// <summary>
+        /// CSV - Write values in quotes 
+        /// </summary>
+        public Boolean ValueInQuotes { get; set; }
+
+        /// <summary>
+        /// URI for the editor that called save results
+        /// </summary>
+        public string OwnerUri { get; set; }
+    }
+
+    /// <summary>
+    /// Parameters for the save results result
+    /// </summary>
+    public class SaveResultRequestResult
+    {
+        /// <summary>
+        /// Error messages for saving to file. 
+        /// </summary>
+        public string Messages { get; set; }
+    }
+
+    public class SaveResultsAsCsvRequest
+    {
+        public static readonly
+            RequestType<SaveResultsRequestParams, SaveResultRequestResult> Type =
+            RequestType<SaveResultsRequestParams, SaveResultRequestResult>.Create("query/save");
+    }
+
+}