Added base survey package.
Updated .gitignore with target output from Maven.
Added stub for Question interface.
Stub interface for Answers.
Renamed package to 'core' to better designate its role.
Added engine package and basic package-info.
Added package for acceptance tests.
Added JUnit to POM.
Added the AnswerListener interface, which allows the survey to react to
answered questions.
Moved AnswerListener to engine package.
Added the QuestionCompletionListener interface.
Added the Section interface.
Removed the AnswerListener.
Added the SurveyBlackboard interface, and added a dependency on Guava.
Added the common package.
Added the simplest possible answer.
Added basic TrueFalseQuestion.
Added the QuestionAsker interface.
Added stub for the SurveyDriver class.