Allow more control over votes generated using devel generate

This is my first significant contribution to any open source project. I have wanted to contribute to Drupal for a long time, in gratitude for all the awesomeness others have put into it already. By necessity, I began working on fixing and extending the vote generation code, but then I continued working on it until it was basically feature-complete for all of VotingAPI's capabilities (as of 7.x-2.11).

Here are the features it now supports from the admin UI:

• independent criteria to delete and generate votes:
  • entity type
  • node types (when entity type is node)
  • vote tags (multi-axis voting categories)
• percent, points, and option vote value types fully supported, for all possible values
• easy presets for some of the most common voting widgets
• custom settings accept an arbitrary list of vote values, to support ANY VotingAPI widget
• powerful statistical models generate very realistic votes with a useful diversity of results

CAVEATS:

• This code cannot generate votes for "rated while editing" widgets offered by the Fivestar module, which are stored in a field on the entity, not with VotingAPI.
• I attempted to update Drush support for the new features, but I have not tested ANY of this with Drush. I was only focused on the admin UI and statistical models. So if you prefer using Drush to generate votes, you might experience some bugs with this code. Drush users, please test and let me know!
• I tried to avoid changing any public function signatures, but there are some changes to the option array structures, STRICTLY limited to generation and deletion of fake votes. So if any of your scripts call existing functions to generate or delete fake votes, you might have to make some changes. This should not affect most users.
• The one edge-case widget type I haven't fully supported is one which would accept an infinite number of possible values, such as a slider widget that produces floating point values. I don't believe any such widget exists currently, although the VotingAPI would support that. But I HAVE made it possible to generate votes with any FINITE number of values, including floating point values, which should be sufficient for testing such a widget, if it ever exists.

Other than the caveats described above, the new vote generation features work very well. I included fairly robust validation, error handling, and user feedback. I tested with the Fivestar module and the Rate module, under many different widget configurations. The results are very realistic, based on statistical models that produce Gaussian distributed user biases, and voting averages that converge on specific random target values (instead of always 50%).

I have tried to follow the Drupal coding standards, but I hope you'll forgive me if I haven't conformed entirely to the "Drupal way". I haven't written any documentation for it, but the code is very well commented, and the admin UI has fairly clear descriptions for all inputs, so hopefully it's all self-explanatory.

Attached are drop-in replacements for votingapi.drush.inc and votingapi.admin.inc, modified from the latest stable release, VotingAPI 7.x-2.11. (These two files are unchanged in the current dev snapshot.) No database changes are required, although you might have to clear the admin menu cache to see the new vote generation UI. As with any update, backup first. Then just copy these two files into your sites/___/modules/votingapi folder, overwriting the originals. The admin UI can be found at SITE/admin/config/development/generate/votingapi

I would avoid installing these files on a production site until it's tested a lot more.