Update parent and copyright year

see #2940
Add sonatype.org as DM

see #2940
Set release version 2.1

finish #2940
Update parent, set sonatype.org as DM

see #2942
Set izpack-singlejar-assembly release version 1.4

finish #2942
Update parent, set sonatype.org as DM

see #2941
Set izpack-singlejar release version 2.5

finish #2941