FIX issue #3: adding foreign key constrains to link tables
FIX issue #3: add class dependencies as on class master and correct the conflicts generated

Merge branch 'master' of https://github.com/jbouhier/2SN into dev

Conflicts:
	app/cache/dev/annotations/b817c1cd4d39550904f9c8b835c64df93b87481e$receiver.cache.php
	app/cache/dev/annotations/b817c1cd4d39550904f9c8b835c64df93b87481e$sender.cache.php
	app/logs/dev.log