Fix for default user not being in the sudo group (LP: #1228228).
add default user to 'sudo' group.

Ubuntu images in 12.04 added the user to the 'admin' group.
The admin group was deprecated/replaced with the 'sudo' group in 12.10.

d-i adds its first-user to the 'sudo' group, so it makes sense to mimic
that behavior for the default user created by cloud-init.  That was the
original reason behind the presense in the 'admin' group.

Also, here I sorted alphabetically the group list.
Fix typo in mkpasswd command: '-s' was used instead of '-R' for salt rounds.
Remove duplicate 'password' text.
Reordered several imports in order for test suite to pass.
use long format args rather than short
fix permission changes
examples/cloud-config-user-groups.txt doc fix, fix pep8

fix documentation of mkpasswd usage in 
doc/examples/cloud-config-user-groups.txt

Also, Precise's version of pep8 insists on ordering of imports, but saucy's
has not.  So we had some incorrect ordering.  This fixes './tools/run-pep8'
on precise.
cc_growpart: respect /etc/growroot-disabled 

cloud-initramfs-growroot is an initramfs module in cloud-initramfs-tools
that resizes the root partition before the root is pivoted over.

growroot was used in Ubuntu up to and including 12.10.  The file
/etc/growroot-disabled on the root filesystem was the only way of
disabling the growing of the root partition.

In cloud-init 0.7.2 cloud-init began resizing the root partition
as growpart gained the ability to utilize 'ptupdate' in kernels > 3.8.
This was a big improvement as now the user could disable or enable
the growing of the root partition via user-data.

In order to let users disable growing of / very simplistically cloud-init
will now respect the presense of /etc/growroot-disabled unless config
specifically tells it to ignore that file.