DESCRIPTION updated, additional doc

- Clean up and addition of pkg details to DESCRIPTION. Moved RJDBC to
Depends as some of its methods need to be available for this package to
work.
- Documented and exported dbSendQuery (basically copy from S-U's RJDBC)
Added test infrastructure
Updated doc
Remove test infrastructure for time being
Updated README
Added NEWS
Revert "Remove need to call jdbc_class_path()"

This reverts commit d2935a53161ba4ed53921781c3239aaae978e961.
Updated README
Move RJDBC back to Imports from Depends

Looks like RSQLServer should be used by loading DBI. See
https://github.com/rstats-db/RSQLite/blob/eb88e758fbea8fa29d74a5d4b1c31a9db503d3ea/README.md