add converters
entities API development
apply new entities API to DAO
JPA converters implementation
database structure reorganization
apply entities API changes on web-moduel
JPA entities implementation
test redevelopment
update hibernate to 4.3.5 version
move to one configuration file of persistence layer
Merge pull request #49 from Alex-Diez/jpa-redevelopment

Jpa redevelopment
test for entities API
Merge pull request #52 from Alex-Diez/jpa-redevelopment

test for entities API