Progressive Results Part 2: Result Completion Event (#134)

The main change in this pull request is to add a new event that will be fired upon completion of a resultset but before the completion of a batch. This event will only fire if a resultset is available and generated.

Changes:
* ConnectionService - Slight changes to enable mocking, cleanup 
* Batch - Moving summary generation into ResultSet class, adding generation of ordinals for resultset and locking of result set list (which needs further refinement, but would be outside scope of this change)
* Adding new event and associated parameters for completion of a resultset. Params return the resultset summary
* Adding logic for assigning the event a handler in the query execution service
* Adding unit tests for testing the new event /making sure the existing tests work
* Refactoring some private properties into member variables

* Refactor to remove SectionData class in favor of BufferRange

* Adding callback for batch completion that will let the extension know that a batch has completed execution

* Refactoring to make progressive results work as per async query execution

* Allowing retrieval of batch results while query is in progress

* reverting global.json, whoops

* Adding a few missing comments, and fixing a couple code style bugs

* Using SelectionData everywhere again

* One more missing comment

* Adding new notification type for result set completion

* Plumbing event for result set completion

* Unit tests for result set events

This includes a fairly substantial change to create a mock of the
ConnectionService and to create separate memorystream storage arrays. It
preserves more correct behavior with a integration test, fixes an issue
where the test db reader will return n-1 rows because the Reliable
Connection Helper steals a record.

* Adding locking to ResultSets for thread safety

* Adding/fixing unit tests

* Adding batch ID to result set summary

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

@@ -0,0 +1,22 @@
+// 
+// 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.ServiceLayer.Hosting.Protocol.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts
+{
+    public class QueryExecuteResultSetCompleteParams
+    {
+        public ResultSetSummary ResultSetSummary { get; set; }
+
+        public string OwnerUri { get; set; }
+    }
+
+    public class QueryExecuteResultSetCompleteEvent
+    {
+        public static readonly
+            EventType<QueryExecuteResultSetCompleteParams> Type =
+            EventType<QueryExecuteResultSetCompleteParams>.Create("query/resultSetComplete");
+    }
+}

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

@@ -15,6 +15,11 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts
         /// </summary>
         public int Id { get; set; }
 
+        /// <summary>
+        /// The ID of the batch set within the query
+        /// </summary>
+        public int BatchId { get; set; }
+
         /// <summary>
         /// The number of rows that was returned with the resultset
         /// </summary>