updates and cleanups to the gem meta

Just modernizing stuff and moving to the latest standards I use in
my gems.
modernize the test suite and get on the latest Assert

This test suite was mega-old.  I had changed a lot of testing
conventions since I last touched this gem so this is me updating
things.  Includes getting on the latest Assert and restructuring
the tests with the standard support, system, unit folder structure.
add a license to the gemspec
cleanup code and organization

Just cleaning things up to get it up to my standards.
need to keep benchmarking Rake tasks around

Accidentally removed them in earlier cleanups.
Merge pull request #19 from kellyredding/kr-testsuite

Cleanups