Hi,
because there is no comment function here an update for
=> the new Debian image 8.3 created on 17th February has now the ability to resize root folder 
admin@ip-172-31-7-159:~$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 16G 0 disk
├─xvda1 202:1 0 1007.5K 0 part
└─xvda2 202:2 0 16G 0 part /
Btw. it has also fixed the "nobootwait" bug where the mount parameter was taken over from Ubuntu cloud package instead using "nofail":
admin@ip-172-31-7-159:~$ cat /etc/cloud/cloud.cfg.d/00_debian.cfg
syslog_fix_perms: root:adm
mount_default_fields: [~, ~, 'auto', 'defaults,nofail', '0', '2']
Bests
Reiner