Add remove step handler for the common case of removing a single service
Fix the wording about reporting differences when mgmt versions differ

The messages "reporting/not reporting differences in the model when mgmt
versions are different" were swapped. Fixed that.
[AS7-6551] Add version 2.0 of jboss-as-config schema.  Also update existing configuration based on 1.4 to use 2.0.
AS7-1534 Add JDBC based timer data store.

This is the initial implementation, and is lacking several important features, however
it does pass the TCK when run using the h2 database.

In particular, the following features are still to come:
- Testing against multiple databases.
- Add a flag to control table creation options
- Clustered timer support
- Setup the test suite to run all timer tests against both data stores