Made both states configurable per user in pillar data
Had to drop extend, for this otherwise the extend would be empty if manage is
False

This will ensure that a given vimrc file in a users home dir is managed
Default it will search for a vimrc in salt://users/files/vimrc/{{ username
}}/vimrc
If this isn't found it will install salt://users/files/vimrc/vimrc

This will ensure a given bashrc file in a users home dir.
Default it will search for a bashrc in salt://users/files/bashrc/{{ username }}/bashrc
If no file is found it will install the default from
salt://users/files/bashrc/bashrc

This adds the ability to manage the ~/.ssh/config file for users.

Example pillar:

ssh_keys:
  id_rsa:
    privkey: |
      -----BEGIN RSA PRIVATE KEY-----
      MIIEowIBAAKCAQEAoQiwO3JhBquPAalQF9qP1lLZNXVjYMIswrMe2HcWUVBgh+vY
      U7sCwx/dH6+VvNwmCoqmNnP+8gTPKGl1vgAObJAnMT623dMXjVKwnEagZPRJIxDy
      B/HaAre9euNiY3LvIzBTWRSeMfT+rWvIKVBpvwlgGrfgz70m0pqxu+UyFbAGLin+
      GpxzZAMaFpZw4sSbIlRuissXZj/sHpQb8p9M5IeO4Z3rjkCP1cxI
      -----END RSA PRIVATE KEY-----
    pubkey: |
      ssh-rsa MIIEowIBAAKCAQEAoQiwO3JhBquPAalQF9qP1lLZNXVjYMIswrMe2H....

permissions.

Signed-off-by: Tim Jones <me@prototim.com>

https://github.com/saltstack/salt/issues/2142

This has been causing issues for many people, as the remove_groups options is undocumented.  In the 2014.7 release this is changing, and remove_groups will default to false:
https://github.com/saltstack/salt/issues/13276

I'm going with false by default, as it's our use case and it will soon be the default.  If people believe this module should default to true and remove groups not listed, I think that's open for discussion, but we should at least add the option.

This also made it necessary to introduce an additional entry 'shell' into the
users lookup table as the formula previously conflated the shell used for
running the visudo command and the default shell to be used for user accounts.

Fixes: #48

Since we are using bash specific features and sometimes you can end up getting /bin/sh - see https://github.com/saltstack-formulas/users-formula/pull/30#issuecomment-44224106

It doesn't by default everywhere - without this the sudo_rules option won't work

Fixes #22

Since ebe5198f, if a user's pillar dict didn't contain sudo_rules, a broken
file.append state would be rendered (since some text is required). With
this patch, the file is still created/managed by the previous state, but
will be empty by default if created fresh. This seems a more sensible
default than assuming a default sudoer policy.

Further, since the first word on each rule line should be the user's
name, that is now assumed.