Update readme (download links).

Author: awulkiew

README.md

@@ -16,11 +16,7 @@ Feel free to report bugs, propose features and create pull requests. Any help is
 
 ##### Download
 
-You can download this extension from [Visual Studio Gallery](https://visualstudiogallery.msdn.microsoft.com/4b81868b-8901-408f-a28e-25a6580788fb).
-
-##### Contact
-
-You may contact me at [Boost.Geometry mailing list](http://lists.boost.org/mailman/listinfo.cgi/geometry).
+You can download this extension from [Visual Studio Marketplace](https://marketplace.visualstudio.com/items?itemName=AdamWulkiewicz.GraphicalDebugging) or [GitHub](https://github.com/awulkiew/graphical-debugging/releases).
 
 ##### Instructions