Cleanup the row text step definitions.

- Adds helper method `getTableRow()`.
- Adds new step definition for finding text in a table row.
Logic for role assignment pushed into the Drupal Drivers.
Actually search for the text in the found row.
Region is a string in getRegion().
Working D8 role creation.
More D8 role cleanup.
Init roles.
Merge pull request #73 from jhedstrom/user-role-fix

User role fix