Renamed Dao implementation classes to '<Entityname>HibernateDao'.

JIRA:
CG-78
Added Dao Interfaces

From now on, Daos are specified in an Interface ('<Entityname>Dao') that extend the interface
'GenericDao'.

JIRA:
CG-78
Dao classes implement their interfaces

Each entity has a corresponding dao class, called '<Entityname>HibernateDao' which indicates, that it
implements the interface '<Entityname>Dao' using hibernate transactions.

Furthermore, each of them extends the class 'GenericHibernateDao'.

JIRA:
CG-78
Adjust xml config for new data abstraction structure

JIRA:
CG-78
Add javadoc and license headers

JIRA:
CG-78
Added insert of dummy user to sql script

In the new database schema, every recipe belongs to a given user. Because webkochbuch does not support
user management completely at the moment, a simple dummy user is created with the create_tables sql
script. This dummy user will implicitly be set as the owner of newly created recipes.

JIRA:
CG-78