Updating to Behat 3.
Initial work to port to Behat 3.
Further work towards Behat 3.

* Continues to extend the Mink Context
* Adds the Behat Chained Steps Extension
* Further API changes.
Making getRegion() public instead of protected.
Removing use of chained steps.
Updating behat.yml for additional profiles.
Follow-up to commit d073a4bd to remove chained steps.
Fixing extensions in behat.yml.
Removing reference to EventInterface.
Parameter name changes.
Compiler passes changes.
Better error handling for missing drupal_root.
Properly setting default driver.
Updating FeatureContext to run properly.

* Without subcontexts, the Behat FeatureContext has been copied directly
  into ths FeatureContext.
Better exception text for missing drupal_root.
Fixing driver setter logic.
Removing conflation between test suites and reserved '@drush' tag.
Updating Drupal8 core nodeCreate() to be compatible methods invoking createNode().
Merge pull request #34 from grasmash/master

Updating Drupal8 core nodeCreate() to be compatible methods invoking cre...
Removing conflation between test suites and reserved '@drush' tag.