Remove "IE hack" from Liquibase XML.

The "IE hack" is the extra space in front of the /> in an empty tag.
I'm removing it because when REXML write documents it doesn't place it
in there and I don't want the first changeset added automatically by
buildr to result in a noisy diff.
Manage Liquibase changeset files with Buildr.
Add initial Liquibase script.

Also reconcile values in Hibernate annotations with Liquibase script.
Generalized database setup in deploy scripts.

Also get Gutterball running Liquibase during deployment.
Update README with information on liquibase task.
Remove old gen-db-update.py and default to changelog.xml.
Allow configurable liquibase file prefix.
Correct Checkstyle errors.
Reconcile model classes with DB schema.
Using Liquibase for tests; not a Hibernate generated schema.

This functionality is implemented via a JUnit rule.  More information
about Rules is available at https://github.com/junit-team/junit/wiki/Rules
fixed reference to changeset in deploy script
Merge pull request #733 from candlepin/awood/gb-liquibase

Awood/gb liquibase