PLF-5900 : Use EXOGTN for eXo Platform Community
PLF-5684 : Declare the source release package used to bundle all PLF sources
Use maven-parent-pom 13

Conflicts:
	pom.xml
CAL-915 Activity of exception event is deleted after delete recurring events
Merge branch 'feature/stabilization'
Merge branch 'master' into feature/stabilization
Merge commit '14bfff68d83f9e70d5a4f2d8faeafd9feacfdeea' into HEAD