Clear and rebuild IntelliSense cache (#238)

* Stage changes to other machine

* IntelliSense cache rebuild command

* Move to other machine

* Add a test for overwriting binding queue.

* Move event handler into lanaguageservice.cs

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/Contracts/RebuildIntelliSenseNotification.cs

@@ -0,0 +1,30 @@
+//
+// 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.LanguageServices.Contracts
+{
+    /// <summary>
+    /// Parameters to be sent back with a rebuild IntelliSense event
+    /// </summary>
+    public class RebuildIntelliSenseParams
+    {
+        /// <summary>
+        /// URI identifying the file that should have its IntelliSense cache rebuilt    
+        /// </summary>
+        public string OwnerUri { get; set;  }        
+    }
+
+    /// <summary>
+    /// RebuildIntelliSenseNotification notification mapping entry 
+    /// </summary>
+    public class RebuildIntelliSenseNotification
+    {
+        public static readonly 
+            EventType<RebuildIntelliSenseParams> Type =
+            EventType<RebuildIntelliSenseParams>.Create("textDocument/rebuildIntelliSense");
+    }
+}