support for ExecuteScalar method

[raoprashanth007]

Please let me know if we can support ExecuteScalar in future release.

[half-ogre]

As I am sure you have already gathered from me neglecting issues on this repo, I am no longer (and haven't been for years) maintaining this library. I apologize it has taken me this long to properly respond to this to let you know, and to archive this repo.