Add 'non_unique' argument to user functions.

* fabtools.user.create
* fabtools.user.modify
* fabtools.require.users.user

When non_unique=True, it allows to create or modify a user account with
a duplicate (non-unique) UID.
Corrects the default value of 'non-unique' agrument.

The default value is now `False`
Add test for creating user with non-unique uid.
Import git module into the top-level module namespace
Refactor git test fabfile
First version of Archlinux support
Update OpenVZ guest context manager for Fabric 1.6.0 [#97]
Fix bug in `supported_locales` (thanks to Bruno Adele)

When no line in the file matched the pattern, grep returned 1, which
made the operation fail.
PEP8
For Archlinux compatibility
First locale support for Archlinux
locale.gen for Archlinux
It's better to do one assestion per test.
You get exact tets failure reason from test name then.
It's better to do one assestion per test.
You get exact tets failure reason from test name then.
Adds authorized key for user
PEP8 compliance in user module
Its easier to use keys from local file than key from string
Adds authorized_keys support in users api
Unsued imports
Documentation fixes for user.authorize_keys