priority sort on views (casetracker_views.module)

Currently only status state and case number could be used as sort in the views (casetracker_views.module,v 1.9 2007/11/12) as from the code.

    'sorts' => array(
      'case_number' => array(
        'help'       => t('Sort by Case Tracker case number.'),
        'name'       => t('Case Tracker: Case Number'),
        'sortable'   => TRUE,
      ),
      'case_status_id' => array(
        'help'       => t('Sort by Case Tracker status state.'),
        'name'       => t('Case Tracker: Case Status'),
        'sortable'   => TRUE,
      ),

What about adding piority too?

      'case_priority_id' => array(
        'help'       => t('Sort by Case Tracker priority state .'),
        'name'       => t('Case Tracker: Case Priority'),
        'sortable'   => TRUE,
      ),

Patch attached.