Update ruby version to latest 2.1.1
Bundle update all gems to latest version.

Remove debugger as its not supported on ruby 2.1
Remove pessimistic version constraints and bundle update.

Avoid specifying versions until necessary.
http://prioritized.net/blog/embracing-promiscuous-gemfiles/
Add @maccman's rack-standards gem.
Use rack-standards gem and remove standards class from lib.
Add @maccman's sprockets-memcache-store gem.
Remove sprockets cache lib as its been replaced with gem.
Merge pull request #4 from javierjulio/update-ruby-and-gem-dependencies

Update ruby and gem dependencies