Merge pull request #6 from ecl1pse/master

Gemspec and hide pid
Require at least stripe 1.8.4, updated Gemfile, ignore Gemfile.lock. Fixes #7
Version bump to 1.8.4.4
Updated readme
Added method to generate card tokens. Closes #5
Updated readme
Version bump to 1.8.4.5
Support DELETE operation on plans
Stripe API returns 404 on not found
Instructions for how to use subscriptions and plans.