Add Font Awesome as a dependency

Or maybe an option for the configuration backend to select the css file ?

Here's a suggestion for a solution:

With an additional option in configuration backend you can select the ccs file as a library variant.
Depending on the setting the following files are loaded via the library api:

Variant 'complete':
=> build/shariff.complete.css
=> build/shariff.complete.js

Variant 'min':
build/shariff.min.css
build/shariff.min.js

Loading library variant:

// Load shariff library.
$variant = variable_get('shariff_css', 'min');
libraries_load('shariff', $variant);

Yes....You're right! (some typos)

Variant 'complete':
=> build/shariff.complete.css
=> build/shariff.min.js

and

$form['shariff_css'] = array(
    '#title' => t('CSS'),
    '#description' => t('Please choose a css variant.'),
    '#type' => 'radios',
    '#options' => array(
      'min' => t('Min. (shariff.min.css => If Font Awesome is already included in your site)'),
      'complete' => t('Complete (shariff.complete.css => Contains all dependencies)'),
    ),
    '#default_value' => $settings['shariff_css'],
  );

Here is a patch for the latest dev version ("data-twitter-via" commit included => there was an overlap)

I think it makes no sense, to take the variable for the css file in the settings array?
Here's another change.

Great idea! I also have another suggestion for a fourth variant "custom": The "shariff.min.js" file and a custom css file within the module? (example: shariff/css/shariff_custom.css)

What do you think about the term "none" instead of "naked" as an option for the variant without css?
The loading of libraries I've changed to a switch statement.

The css file option "custom" is for your own css definitions. I thought it would be better if the custom css for the shariff module remains within the module and not in the theme?

You're right, I'll rename the library variant as you suggested.

I have tested all the options and the default value for the css file already included in: shariff_settings_form()

 '#default_value' => variable_get('shariff_css', 'min'),

The new patch comes later ... unless you're faster;-)

You're right with the custom css file ... that makes no sense. I have modified the README.txt and changed the option text for the variant selection "naked" to "none". I think this patch is quite good and hope you like it too!

I am very pleased with the result of our work. I look forward to the new version. Many Thanks!