Changes

tsk5 Changes id generation, adds class Story to persistence.xml file,
create StoryEJB, adds testEJB and fix stories.xml and stories DataSet
The id changes are mades to avoid the creation of a table calls
hibernate. In the persistence.xml (service), the story class adds to
creates in DB. Adds StoryEJB ,this contains a method to get 6 recent
stories. Also,adds TestStoryEJB and TestSuite adds configuration to test
method getRecentStories from StoryEJB. On StoryDataset adds method
recent Stories to get last 6 Stories to compares to method
getRecentStories in the TestStoryEJB.
Fixes: stories.xml (adds six correct dates). Theme.java add correct
enum, changes story for HISTORIC, SCIFI for SCIENCE_FICTION and CHILDISH
for CHILD.