Rename of Exercise and package exercise to Vocabulary, vocabulary respectively.
Refactored test suite.

modified:   Java/Exercise/.project
deleted:    Java/Exercise/Test/exercise/ExerciseListTest.java
new file:   Java/Exercise/Test/vocabulary/ExerciseListTest.java
renamed:    Java/Exercise/Test/exercise/ExerciseObjectTest.java -> Java/Exercise/Test/vocabulary/ExerciseObjectTest.java
renamed:    Java/Exercise/Test/exercise/ExerciseTest.java -> Java/Exercise/Test/vocabulary/ExerciseTest.java
deleted:    Java/Exercise/src/exercise/TestProg.java
renamed:    Java/Exercise/src/exercise/Exercise.java -> Java/Exercise/src/vocabulary/Vocabulary.java
renamed:    Java/Exercise/src/exercise/ExerciseList.java -> Java/Exercise/src/vocabulary/VocabularyList.java
renamed:    Java/Exercise/src/exercise/ExerciseObject.java -> Java/Exercise/src/vocabulary/VocabularyObject.java