Feature execution plan settings and request implementation (#213)

* experimental showplan implementation (tools side only)

* fix for redundant massages from showplan executions

* moved showplan batches to new variables to make it less confusing

* returns showplan as part of batch summary with in each result summary

* cleaned up showplan resultsets

* cleaning up code and making showplan var optional

* changes all var names to showplan

* adding estimated support

* small fixes

* updatin var names and adding EPOptions struct

* adding ssms execution plan logic based on server types

* adding special actions logic

* removing redundant name changes

* execution plan query handler added

* cleaning up functions and data structures

* seperated special actions into its own class

* cleaning up special actions

* cleaning up code

* small new line fixes

* commenting out pre-yukon code

* removing all pre yukon code

* last yukon code commented out

* fixes broken tests

* adding related unit tests; integration tests incoming

* finishing tests and cleaning up code

* semantic changes

* cleaning up semantics

* changes and test fixes, also adding new exceptions into RS

* fixing special actions and cleaning up request logic

* fixing comment to trigger new build

* triggering another  build

* fixed up specialaction and added tests for it

test/Microsoft.SqlTools.ServiceLayer.Test/QueryExecution/SpecialActionTests.cs

@@ -0,0 +1,79 @@
+//
+// 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.QueryExecution;
+using Microsoft.SqlTools.ServiceLayer.Test.Utility;
+using Xunit;
+
+namespace Microsoft.SqlTools.ServiceLayer.Test.QueryExecution
+{
+    public class SpecialActionTests
+    {
+
+        [Fact]
+        public void SpecialActionInstantiation()
+        {
+            // If:
+            // ... I create a special action object 
+            var specialAction = new SpecialAction();
+
+            // Then:
+            // ... The special action should be set to none and only none
+            Assert.Equal(true, specialAction.None);
+            Assert.Equal(false, specialAction.ExpectYukonXMLShowPlan);
+        }
+
+        [Fact]
+        public void SpecialActionNoneProperty()
+        {
+            // If:
+            // ... I create a special action object and add properties but set it back to none 
+            var specialAction = new SpecialAction();
+            specialAction.ExpectYukonXMLShowPlan = true;
+            specialAction.None = true;
+
+            // Then:
+            // ... The special action should be set to none and only none
+            Assert.Equal(true, specialAction.None);
+            Assert.Equal(false, specialAction.ExpectYukonXMLShowPlan);
+        }
+
+        [Fact]
+        public void SpecialActionExpectYukonXmlShowPlanReset()
+        {
+            // If:
+            // ... I create a special action object and add properties but set the property back to false 
+            var specialAction = new SpecialAction();
+            specialAction.ExpectYukonXMLShowPlan = true;
+            specialAction.ExpectYukonXMLShowPlan = false;
+
+            // Then:
+            // ... The special action should be set to none and only none
+            Assert.Equal(true, specialAction.None);
+            Assert.Equal(false, specialAction.ExpectYukonXMLShowPlan);
+        }
+
+        [Fact]
+        public void SpecialActionCombiningProperties()
+        {
+            // If:
+            // ... I create a special action object and add properties and combine with the same property 
+            var specialAction = new SpecialAction();
+            specialAction.ExpectYukonXMLShowPlan = true;
+
+            var specialAction2 = new SpecialAction();
+            specialAction2.ExpectYukonXMLShowPlan = true;
+
+            specialAction.CombineSpecialAction(specialAction2);
+
+            // Then:
+            // ... The special action should be set to none and only none
+            Assert.Equal(false, specialAction.None);
+            Assert.Equal(true, specialAction.ExpectYukonXMLShowPlan);
+        }
+
+
+    }
+}