If GECOS info is not specified, it should not be deleted either.
Add function config.is_true

This function will provide a common interface for determining truth, so
that module functions can properly determine the truthiness of a value
passed in via the CLI.

This will allow some code in the package providers to be a little less
ugly, and will also come in handy when #3363 is implemented.
docstring modifications to make docs look pretty
mode docstring tweaks
Merge pull request #4054 from terminalmage/issue2783

Add function config.is_true
Remove faulty test

Can't pass a group name in as the gid, a gid is required
Fix #4054, add a cli example
Merge pull request #4055 from grischa/user-present

Two changes for a more robust user.present state