Added rudimentary pack structures for Vanguard, VS System, and Yu-Gi-Oh.

This makes it easier to add new keys to the non-english locales.

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Removed extra dependancy from Magic export template.

- Updated statistics.
- No more auto-bolding of lowercase keywords.

- Upgraded Statistics.
- Scripts refurbished based on latest Magic scripts.

to_real no longer needs to throw exceptions when conversion fails

Split up images exporting, and moved it to data/formats/image

Added toImage function to ScriptValue.

Made condition and default_expand parameters of expand_keywords optional.

As a bonus the keywords and perhaps other reusable parts can now be used by vanguard with "include file: /magic.mse-game/keywords".

  used to: by running scripts on cards and comparing to string value of selected group
  now:     by keeping a list of group_ids for all cards, and comparing indices
Added 'bin size' attribute for making a histogram of numeric axes.
Added 'Text length' statistic.