Speed up deploys!

[jeremyolliver]

No one wants to recompile assets to correct a typo in the text, and why should you have to?

By redefining some capistrano tasks, we can provide features like:

• Only bundle install if the Gemfile, or Gemfile.lock have changed
• Only compile assets if the asset source, or configuration have changed

Inspiration to be drawn from:

http://blog.codeclimate.com/blog/2013/10/02/high-speed-rails-deploys-with-git/

https://github.com/tomafro/recap/tree/1.x/lib/recap/tasks