Handle 'groups=' (empty string) in user module (Linux)

Makes it possible to remove a user from all but the primary group.

Setting 'groups=' is the equivalent to passing '-G ""' to
useradd/usermod, which is interpreted as "no group" on Linux.
added thirsty option to copy
Signed-off-by: Brian Coca <briancoca+dev@gmail.com>
Allow end of line comments in inventory file

See github issue 2702
https://github.com/ansible/ansible/issues/2072
Add an example on how to *add* a %wheel line to sudo - tricky as it has
a colon, which needs some special attention.
Add Linux-style path for sudoers file, to be consistent with other examples.
Add support for NetBSD. Tested on NetBSD 6.0/i386.
Added support for AIX 5.3 and 6.1

A collegue of mine has added basix AIX support to the setup, user and group modules.

We have tested this on AIX 5.3 and 6.1 and it works "as advertised"
Added zfs module
Added zfs example playbook
Adding a simple EC2 volume module for creation and attach
Updated comments and closed code example.
The default for install-recommends is actually Yes, not No, as is
visible on line 121
Merge pull request #2088 from pas256/devel

Documentation fix for apt module: install-recommends
Solving bug https://github.com/ansible/ansible/issues/2004
Now handle positive integer value in virtual files if they are separated
by group of space characters where the count is unpredictable.
Thanks to romeotheriault for filing this bug.
pasto and core connection plugins reference fix
Updated documentation. Works with ansible-doc
Merge branch 'devel' of git://github.com/trendels/ansible into testing
Merge branch 'thirsty_copy' of git://github.com/bcoca/ansible into testing
Slight docs tweak about thirsty mode on the copy module
Merge pull request #2073 from nigelm/hosts_comment_fix

Allow end of line comments in inventory file - fixes #2072