Add more Mirador configuration keys as theme variables.

[alxp]

Mirador's appearance and behaviour is mostly controlled via options passed to the 'window', 'windows' and 'workspace' arrays.

Islandora Mirador should allow modules to add in these options via theme variables.

For example, a module should be able to implement a hook like this:

function mymodule_preprocess_mirador(&$variables) {
  $variables['window_config']['allowClose'] = FALSE;
  }
}

These settings should also be settable when instantiating Mirador's Block object class.