Load 'json' gem in both Mail and TMail examples.
Remove empty development section from Gemfile.
Add #with_retries method.
Add HttpClient mutexes to perform HTTP requests in thread safe manner.
Use Markdown to format README, add more useful examples for using with Mail gem.
Don't use real API key in Bounce API example.
Repeat signatures warning in Mail example.
Fix math in #with_retries method.
Don't use ActiveSupport Array#wrap method. Use Array[*value] instead.
Update README with new code examples, note that TMail is not recommended, other minor improvements.
Use better way to detect ActiveSupport::JSON.
Bump gem version. Update CHANGELOG.
Add tagged message example.
Add Message-ID example, copy improvements.
Remove README.rdoc from the gemspec.
Merge pull request #27 from temochka/master

Thread safety, updated README, various bug fixes, prepared for 0.9.16 release.
Remove unneeded debug output.
Remove date from gemspec, add unicode option for RDOC files.
Bump version number.
Remove unneeded debug output from shared_examples.