Update and rename BingImageInsights.cs to BingGetSimilarImages.cs

Minor changes to readme and program name.

Author: ronak25

…et/Search/Tutorials/BingImageInsights.cs …Search/Tutorials/BingGetSimilarImages.csdotnet/Search/Tutorials/BingImageInsights.cs renamed to dotnet/Search/Tutorials/BingGetSimilarImages.cs dotnet/Search/Tutorials/BingImageInsights.cs renamed to dotnet/Search/Tutorials/BingGetSimilarImages.cs

@@ -1,5 +1,6 @@
 //Copyright (c) Microsoft Corporation. All rights reserved.
 //Licensed under the MIT License.
+//This code allows you to upload a binary image and returns images similar to the one that is uploaded
 //For more information about this sample, see the following documentation:
 // https://docs.microsoft.com/en-us/azure/cognitive-services/bing-image-search/tutorial-image-post