UserPropertyOverloaderTest fixed
new Converters ConverterGender.java and ConverterMembership.java
Experimenting with hibernate persistence

User.java renamed to OxUser
new entities OxAvatar.java, OxProfileData.java and OxUserGroupMembership.java
new base class for CRUD tests: CrudTestBase
UserTest reworked

pom:
  - javax.persistence replaced by org.hibernate.javax.persistence
  - org.slf4j:slf4j-log4j12 added (for hibernate logging)
  - org.hsqldb:hsqldb added (scope test in SDI-plugins-oxwall)

hibernate.cfg.xml renamed to hibernate.cfg.xml_, instead META-INF/persistence.xml introduced
Oxwall-DB reverse engineering.txt added

TargetConfiguration: annotation SdiProps added
some more experiments  with CriteriaBuilder
persistence.xml: mysql connection properties added (commented out)
More experiments with CriteriaBuilder (two items in where clause)