Adds example to set root password

The documentation in README.md states that it is possible to set the root password, but it does not give an example. 

This pull request adds an example of how to set the root password
Merge pull request #341 from spuder/patch-1

Adds example to set root password
Fix an issue with lowercase privileges.

This fixes the case where a user passes in lowercase privileges and
we incorrectly assume this means a change and reapply them.
Force mime-types to < 2.0 as this no longer works on Ruby 1.8.
Merge pull request #342 from apenney/fix/privileges

Fix an issue with lowercase privileges.