OO-2732: implement a matchInteraction with drag and drop (fallback to click possible) with slightly enhanced editor and word export

OO-2708: update qtiworks to 1.0.3, add validation to FIB and hottext editors, fix an issue where a gap text alone in a paragraph is deleted by TinyMCE

OO-2602: skip close step if there are no review and no feedbacks, implement some selenium tests to secure the different flows for different settings

OO-2430: update paypal libraries, fix configuration trailing tab, fix return from paypal, fix transaction sort by date and status in administration, fix missing icon...

OO-2429: move the foreign key from identity to user, remove double mapping of identity, add more unit tests for invitation, unify the methods to create the user and identity

OO-2354: decouple attribute sued to search a user on the LDAP server from the user identifier and make it configurable, add embbeded LDAP server for unit tests

OO-2041: upgrade hibernate and infinispan, update mapping to use TableGenerator with legacy-hilo optimizer

OO-1867: upgrade selenium and arquillian libraries to support Firefox 46 and update the tests to work with them