Update ruby version to 2.0.0-p481.
Merge pull request #706 from knappe/master

Update ruby version to 2.0.0-p481.
use database_rewinder instead of database_cleaner
Update versions for rubygem and ruby.
Drop distinction between mysql and mysql2

The `mysql` gem has been deprecated in favor of the `mysql2` gem.  At this point, we shouldn't make a distinction and just point people to the `mysql2` gem.

This also removes a warning about MySQL in Snow Leopard, which included a typo that has been there for about a year.  Given the length of time the typo existed, I would say we're in the clear to remove the entire warning.
Merge pull request #707 from knappe/patch-2

Update versions of rubygem and ruby.
Merge pull request #708 from knappe/patch-3

Drop distinction between mysql and mysql2
Merge pull request #709 from mcfiredrill/database-rewinder

use database_rewinder instead of database_cleaner
add version to gem test data
Merge branch 'master' into yanked