Fixed edit button appears even if no greeting
Added content negotiation (JSON or HTML) to greetings controller and exception handler
Made test dependant on a testing specific application context, GreetingsAppTestContext
Changed base repository from CrudRepository to a PagingAndSortingRepository
Added support to Cucumber-JVM BDD. Added feature for Greetings JSON API BDD, including list greetings and retrieve greeting scenarios.
Updated artifact name in pom.xml to "greetings"