Test speed improvement

Skipping over repeat executions of low level RSpec tests when doing a
full test run.
Merge branch 'dev' into compatibly_consistent
Gem dependency updates.

Unlocked the version of gherkin depended on by the gem since it is a
non-issue.
Merge branch 'compatibly_consistent' into dev
Merge branch 'dev' into release_prep
History update.

Updating gem history in preparation for v1.5.1 release.
Version bump.

Gem version bumped for v1.5.1 release.