Upgrade Jackson JaxRS json provider to 2.2.2
Webservice web.xml fine tuning
* we don't really need long sessions here
* load the webservices when necessary
Add new patterns to PatternHolder, clarify neptun patterns
Refactor entrants webservice: extract common stuff to an abstract class
* common supperclass for web services like #49
* use patterns from the PatternHolder class
New webservice to query the active memberships of a given user (#49)
Bump version to 2.5.3
* add new webservice to query memberships (#49)
* refactor entrants webservice
* update jackson jaxrs json provider to 2.2.2