added a --cards param that accepts a mixed list of card title and card numbers to include in processing, and a filterCards helper method that uses it to filter the cards from a given cardset
moved declaration of 'img' outside the try..catch, so that if it is successfully loaded, it'll be available for actual processing
added a --debug option for the main command
 * created an Executable interface for commands which can actually be executed
 * enabled card filtering for both validation and composition
 * if --debug is enabled, dump the stack trace when an error is caught by the Executable
 * added try..catch for card validation
got dynamic theme wiring running
moved DefaultIcon.getSize's implementation to SvgUtils so it can be used for arbitrary documents, not just icons
fixed casing of validation level description