Cleaned up files for modern hierarchy.

* Added .gitignore for all of the .NET files.
* Removed the entire VbNini area because it isn't needed for VB support.
* Removed the CSVROOT which was a remnant from the CSV to SVN to Git
  conversion.
* Deleted the old documentation.  It's going to be replaced with the Wiki.
* Moved all of the normal Nini C# code into the root.
* Made the read me file a Markdown file.  It isn't ready yet but it's
  getting there.