Converted remaining filenames to snake case.
Renamed more files.
Merge branch 'convert-more-filenames-to-snakecase' of github.com:keithrbennett/dnsruby into convert-more-filenames-to-snakecase
Renamed (again) Cache.rb to cache.rb.
Merge pull request #23 from keithrbennett/convert-more-filenames-to-snakecase

Converted remaining filenames to snake case.