Run handlers in threads
Be consistent (and support Ruby 1.8)
Implement an option to control threading
Merge pull request #31 from jgorset/feature/threads

Add option to run handlers in threads
Add thread option description
Update travis ruby versions
Add build-status badge
Version bump to 0.5.1
Regenerate gemspec for version 0.5.1
Fix mocha warning
Don't list ignored Gemfile.lock in the gemspec.
Merge pull request #32 from jgorset/fix/gemfile-lock

Don't list ignored Gemfile.lock in the gemspec.
Added callback handler support for before_tick, after_tick, before_run, after_run.