Using Ruby 1.8.7 with proper readline support.

This fixed my guard issue.

(see https://github.com/guard/guard/wiki/Add-proper-Readline-support-to-Ruby-on-Mac-OS-X)
Remove outdated comment.
Fetching gems over http rather then https.

Maybe the certificate has expired... or someone tries to hack us :-)

  Could not verify the SSL certificate for https://rubygems.org/
Stub time via Timecop.
Add documentation for the new snapshot format.
Change snapname timestamp format to ISO 8601.
Raise error when snapname doesn't match ISO 8601 format.
Add zuper prefix to snapname (fixes #1)
Merge branch 'issue_1'