Misc cleanup, tests running on Windows

Starting goal was getting this repo on Jenkins, both build and test, and some cleanup was sorely needed.

High level:
- Dead code removal, cleanup, compiler warning fixes (mostly casts)
- On nix, tests are now build and ran via autotools instead of a custom Makefile
- On Windows, add simple makefile and batch script for running tests.
    - Much searching showed no way to use an ODBC ddl *without* installing it so require installer built and use that
    - This will require `runas` or disabled UAC on the Jenkins machine but that seems reasonable
- Test path/organization cleanup. I just about got rid of test_runner.py altogether, as a script and diff should be able to do the trick, but leave it for now.